diff --git a/backend/Cargo.lock b/backend/Cargo.lock
index d62a184..697b2de 100644
--- a/backend/Cargo.lock
+++ b/backend/Cargo.lock
@@ -627,6 +627,7 @@ dependencies = [
  "diesel_migrations",
  "dotenv",
  "email_address",
+ "governor",
  "hyper 1.6.0",
  "lettre",
  "mockall",
@@ -638,6 +639,7 @@ dependencies = [
  "serde_json",
  "tera",
  "thiserror 2.0.11",
+ "tokenbucket",
  "tokio",
  "tower 0.5.2",
  "tower-http",
@@ -1006,6 +1008,20 @@ dependencies = [
  "syn",
 ]
 
+[[package]]
+name = "dashmap"
+version = "6.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5041cc499144891f3790297212f32a74fb938e5136a14943f338ef9e0ae276cf"
+dependencies = [
+ "cfg-if",
+ "crossbeam-utils",
+ "hashbrown 0.14.5",
+ "lock_api",
+ "once_cell",
+ "parking_lot_core",
+]
+
 [[package]]
 name = "data-encoding"
 version = "2.7.0"
@@ -1292,6 +1308,12 @@ version = "1.0.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "3f9eec918d3f24069decb9af1554cad7c880e2da24a9afd88aca000531ab82c1"
 
+[[package]]
+name = "foldhash"
+version = "0.1.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d9c4f5dac5e15c24eb999c26181a6ca40b39fe946cbe4c263c7209467bc83af2"
+
 [[package]]
 name = "foreign-types"
 version = "0.3.2"
@@ -1373,6 +1395,12 @@ version = "0.3.31"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "f90f7dce0722e95104fcb095585910c0977252f286e354b5e3bd38902cd99988"
 
+[[package]]
+name = "futures-timer"
+version = "3.0.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "f288b0a4f20f9a56b5d1da57e2227c661b7b16168e2f72365f57b63326e29b24"
+
 [[package]]
 name = "futures-util"
 version = "0.3.31"
@@ -1418,8 +1446,10 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "43a49c392881ce6d5c3b8cb70f98717b7c07aabbdff06687b9030dbfbe2725f8"
 dependencies = [
  "cfg-if",
+ "js-sys",
  "libc",
  "wasi 0.13.3+wasi-0.2.2",
+ "wasm-bindgen",
  "windows-targets 0.52.6",
 ]
 
@@ -1453,6 +1483,29 @@ dependencies = [
  "walkdir",
 ]
 
+[[package]]
+name = "governor"
+version = "0.10.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3cbe789d04bf14543f03c4b60cd494148aa79438c8440ae7d81a7778147745c3"
+dependencies = [
+ "cfg-if",
+ "dashmap",
+ "futures-sink",
+ "futures-timer",
+ "futures-util",
+ "getrandom 0.3.1",
+ "hashbrown 0.15.2",
+ "nonzero_ext",
+ "parking_lot",
+ "portable-atomic",
+ "quanta",
+ "rand 0.9.1",
+ "smallvec",
+ "spinning_top",
+ "web-time",
+]
+
 [[package]]
 name = "group"
 version = "0.12.1"
@@ -1523,6 +1576,11 @@ name = "hashbrown"
 version = "0.15.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "bf151400ff0baff5465007dd2f3e717f3fe502074ca563069ce3a6629d07b289"
+dependencies = [
+ "allocator-api2",
+ "equivalent",
+ "foldhash",
+]
 
 [[package]]
 name = "headers"
@@ -2470,6 +2528,12 @@ dependencies = [
  "memchr",
 ]
 
+[[package]]
+name = "nonzero_ext"
+version = "0.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "38bf9645c8b145698bb0b18a4637dcacbc421ea49bef2317e4fd8065a387cf21"
+
 [[package]]
 name = "nu-ansi-term"
 version = "0.46.0"
@@ -2819,6 +2883,12 @@ dependencies = [
  "typemap",
 ]
 
+[[package]]
+name = "portable-atomic"
+version = "1.11.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "350e9b48cbc6b0e028b0473b114454c6316e57336ee184ceab6e53f72c178b3e"
+
 [[package]]
 name = "postgres-protocol"
 version = "0.6.7"
@@ -2916,6 +2986,21 @@ dependencies = [
  "cc",
 ]
 
+[[package]]
+name = "quanta"
+version = "0.12.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "3bd1fe6824cea6538803de3ff1bc0cf3949024db3d43c9643024bfb33a807c0e"
+dependencies = [
+ "crossbeam-utils",
+ "libc",
+ "once_cell",
+ "raw-cpuid",
+ "wasi 0.11.0+wasi-snapshot-preview1",
+ "web-sys",
+ "winapi",
+]
+
 [[package]]
 name = "quick-error"
 version = "1.2.3"
@@ -2978,6 +3063,16 @@ dependencies = [
  "rand_core 0.6.4",
 ]
 
+[[package]]
+name = "rand"
+version = "0.9.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "9fbfd9d094a40bf3ae768db9361049ace4c0e04a4fd6b359518bd7b73a73dd97"
+dependencies = [
+ "rand_chacha 0.9.0",
+ "rand_core 0.9.3",
+]
+
 [[package]]
 name = "rand_chacha"
 version = "0.1.1"
@@ -2998,6 +3093,16 @@ dependencies = [
  "rand_core 0.6.4",
 ]
 
+[[package]]
+name = "rand_chacha"
+version = "0.9.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d3022b5f1df60f26e1ffddd6c66e8aa15de382ae63b3a0c1bfc0e4d3e3f325cb"
+dependencies = [
+ "ppv-lite86",
+ "rand_core 0.9.3",
+]
+
 [[package]]
 name = "rand_core"
 version = "0.3.1"
@@ -3022,6 +3127,15 @@ dependencies = [
  "getrandom 0.2.15",
 ]
 
+[[package]]
+name = "rand_core"
+version = "0.9.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "99d9a13982dcf210057a8a78572b2217b667c3beacbf3a0d8b454f6f82837d38"
+dependencies = [
+ "getrandom 0.3.1",
+]
+
 [[package]]
 name = "rand_hc"
 version = "0.1.0"
@@ -3084,6 +3198,15 @@ dependencies = [
  "rand_core 0.3.1",
 ]
 
+[[package]]
+name = "raw-cpuid"
+version = "11.5.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "c6df7ab838ed27997ba19a4664507e6f82b41fe6e20be42929332156e5e85146"
+dependencies = [
+ "bitflags 2.8.0",
+]
+
 [[package]]
 name = "rdrand"
 version = "0.4.0"
@@ -3691,6 +3814,15 @@ version = "0.9.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "6980e8d7511241f8acf4aebddbb1ff938df5eebe98691418c4468d0b72a96a67"
 
+[[package]]
+name = "spinning_top"
+version = "0.3.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d96d2d1d716fb500937168cc09353ffdc7a012be8475ac7308e1bdf0e3923300"
+dependencies = [
+ "lock_api",
+]
+
 [[package]]
 name = "spki"
 version = "0.6.0"
@@ -3993,6 +4125,12 @@ version = "0.1.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "1f3ccbac311fea05f86f61904b462b55fb3df8837a366dfc601a0161d0532f20"
 
+[[package]]
+name = "tokenbucket"
+version = "0.1.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "43b432f4112b803f1ced6a45a6639965e6ac7b43e9f39cf758121848300ed525"
+
 [[package]]
 name = "tokio"
 version = "1.43.0"
@@ -4724,6 +4862,16 @@ dependencies = [
  "wasm-bindgen",
 ]
 
+[[package]]
+name = "web-time"
+version = "1.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5a6580f308b1fad9207618087a65c04e7a10bc77e02c8e84e9b00dd4b12fa0bb"
+dependencies = [
+ "js-sys",
+ "wasm-bindgen",
+]
+
 [[package]]
 name = "whoami"
 version = "1.5.2"
diff --git a/backend/Cargo.toml b/backend/Cargo.toml
index bbf9e44..52e14ab 100644
--- a/backend/Cargo.toml
+++ b/backend/Cargo.toml
@@ -45,7 +45,8 @@ axum-extra = { version = "0.10.0", features = ["multipart"] }
 csv = "1.3.1"
 
 lettre = "0.11.14"
-
+tokenbucket = "0.1.6"
+governor = "0.10.0"
 
 
 [dev-dependencies]
diff --git a/backend/migrations/2025-04-22-082248_add_additional_fields_to_mail_for_queueing/down.sql b/backend/migrations/2025-04-22-082248_add_additional_fields_to_mail_for_queueing/down.sql
new file mode 100644
index 0000000..8866867
--- /dev/null
+++ b/backend/migrations/2025-04-22-082248_add_additional_fields_to_mail_for_queueing/down.sql
@@ -0,0 +1,6 @@
+-- Rollback: Remove queuing and rate-limiting fields from mails table
+
+ALTER TABLE mails
+DROP COLUMN scheduled_at,
+DROP COLUMN attempts,
+DROP COLUMN last_error;
\ No newline at end of file
diff --git a/backend/migrations/2025-04-22-082248_add_additional_fields_to_mail_for_queueing/up.sql b/backend/migrations/2025-04-22-082248_add_additional_fields_to_mail_for_queueing/up.sql
new file mode 100644
index 0000000..3f865be
--- /dev/null
+++ b/backend/migrations/2025-04-22-082248_add_additional_fields_to_mail_for_queueing/up.sql
@@ -0,0 +1,6 @@
+-- Migration: Add queuing and rate-limiting fields to mails table
+
+ALTER TABLE mails
+ADD COLUMN "scheduled_at" TIMESTAMPTZ DEFAULT CURRENT_TIMESTAMP NOT NULL,
+ADD COLUMN "attempts" INTEGER DEFAULT 0 NOT NULL,
+ADD COLUMN "last_error" TEXT;
\ No newline at end of file
diff --git a/backend/migrations/2025-04-24-050126_add__rate_limit__column/down.sql b/backend/migrations/2025-04-24-050126_add__rate_limit__column/down.sql
new file mode 100644
index 0000000..be273eb
--- /dev/null
+++ b/backend/migrations/2025-04-24-050126_add__rate_limit__column/down.sql
@@ -0,0 +1,3 @@
+-- Down Migration: remove the rate_limit column
+ALTER TABLE "servers"
+DROP COLUMN IF EXISTS "rate_limit";
\ No newline at end of file
diff --git a/backend/migrations/2025-04-24-050126_add__rate_limit__column/up.sql b/backend/migrations/2025-04-24-050126_add__rate_limit__column/up.sql
new file mode 100644
index 0000000..e40cbe6
--- /dev/null
+++ b/backend/migrations/2025-04-24-050126_add__rate_limit__column/up.sql
@@ -0,0 +1,3 @@
+-- Up Migration: add the rate_limit column with a default value
+ALTER TABLE "servers"
+ADD COLUMN "rate_limit" INTEGER NOT NULL DEFAULT 60;
\ No newline at end of file
diff --git a/backend/src/handlers/bounce_logs_handler.rs b/backend/src/handlers/bounce_logs_handler.rs
index 08a4e70..1bfda59 100644
--- a/backend/src/handlers/bounce_logs_handler.rs
+++ b/backend/src/handlers/bounce_logs_handler.rs
@@ -4,19 +4,24 @@ use std::sync::Arc;
 
 use crate::{error::AppError, models::{bounce_logs::
     { 
-        Message, CreateBounceLogRequest, CreateBounceLogResponse, GetBounceLogResponse, SnsNotification
-    }, mail::UpdateMailRequest}, repositories::{contact::ContactRepositoryImpl, mail_repository::MailRepositoryImpl}, services::{bounce_logs_service, contact_service::ContactService, mail_service::{self, MailService}}
+        CreateBounceLogRequest, CreateBounceLogResponse, GetBounceLogResponse, Message, SnsNotification
+    }, mail::UpdateMailRequest}, repositories::{contact::ContactRepositoryImpl, mail_repository::MailRepositoryImpl}, services::{bounce_logs_service, contact_service::ContactService, mail_service::{self, MailService, MailServiceTrait}}
 };
 
 use axum::{
-    extract:: Path, Json, http::StatusCode
+    extract:: Path, Json, http::StatusCode, Extension
 };
 use uuid::Uuid;
+use crate::utils::bounce_logs::search_header_from_header_list;
 
 enum MailStatus {
     Draft,
-    Pending,
-    Sent,
+    Scheduled,
+    Queued,
+    Processing, // this status might not be necessary...
+    Submitted,
+    Delivered,
+    Failed,
     Bounced,
 }
 
@@ -24,8 +29,12 @@ impl MailStatus {
     pub fn as_str(&self) -> &'static str {
         match self {
             MailStatus::Draft => "draft",
-            MailStatus::Pending => "pending",
-            MailStatus::Sent => "sent",
+            MailStatus::Scheduled => "scheduled",
+            MailStatus::Queued => "queued",
+            MailStatus::Processing => "processing",
+            MailStatus::Submitted => "submitted",
+            MailStatus::Delivered => "delivered",
+            MailStatus::Failed => "failed",
             MailStatus::Bounced => "bounced",
         }
     }
@@ -33,8 +42,12 @@ impl MailStatus {
     pub fn from_str(s: &str) -> Option<Self> {
         match s {
             "draft" => Some(MailStatus::Draft),
-            "pending" => Some(MailStatus::Pending),
-            "sent" => Some(MailStatus::Sent),
+            "scheduled" => Some(MailStatus::Scheduled),
+            "queued" => Some(MailStatus::Queued),
+            "processing" => Some(MailStatus::Processing),
+            "submitted" => Some(MailStatus::Submitted),
+            "delivered" => Some(MailStatus::Delivered),
+            "failed" => Some(MailStatus::Failed),
             "bounced" => Some(MailStatus::Bounced),
             _ => None,
         }
@@ -50,11 +63,9 @@ impl MailStatus {
     )
 )]
 pub async fn handle_sns_notification (
+    Extension(mail_service): Extension<Arc<MailService>>,
     payload: Json<SnsNotification>,
 ) -> Result<(), AppError> {
-    let mail_repository = Arc::new(MailRepositoryImpl);
-    let mail_service = MailService::new(mail_repository);
-
      // automate the subscription confirmation...
      if payload.notification_type == "SubscriptionConfirmation" {
         // subscribe to the public api endpoint...
@@ -74,12 +85,13 @@ pub async fn handle_sns_notification (
             .map_err(|err| AppError::NotFoundError(Some(err.to_string())))?;
 
         if sns_event.notification_type.is_none() {
-            if let Some(event_type) = sns_event.event_type {
-                let mail_id = sns_event.mail.mail_id;
+            if let Some(event_type) = sns_event.event_type.as_ref() {
+                let mail_id = search_header_from_header_list(&sns_event, "mailId")
+                .ok_or_else(|| AppError::NotFoundError(Some("mailId not found in SNS event".to_string())))?;
 
                 match event_type.as_str() {
                     "Open" => {
-                        mail_service.update_mail(mail_id, UpdateMailRequest {
+                        mail_service.update_mail(mail_id,UpdateMailRequest {
                             open: Some(chrono::Utc::now()),
                             ..Default::default()
                         }).await?;
@@ -100,17 +112,19 @@ pub async fn handle_sns_notification (
 
         match sns_event.notification_type.as_ref().unwrap().as_str() {
             "Bounce" => {
-                if let Some(bounce) = sns_event.bounce {
-                    let recipients = bounce.bounced_recipients;
+                if let Some(bounce) = sns_event.bounce.as_ref() {
+                    let recipients = &bounce.bounced_recipients;
 
                     let status = MailStatus::Bounced;
-                    let mail_id = sns_event.mail.mail_id.clone();
-                    let _ = mail_service.update_mail_status(mail_id, status.as_str()).await;
+                    let mail_id = search_header_from_header_list(&sns_event, "mailId")
+                    .ok_or_else(|| AppError::NotFoundError(Some("mailId not found in SNS event".to_string())))?;
+
+                    let _ = mail_service.update_mail_status(mail_id.clone(), status.as_str()).await;
 
                     for recp in recipients {
                         let contact_repository = Arc::new(ContactRepositoryImpl);
                         let contact_service = ContactService::new(contact_repository);
-                        let contact = contact_service.get_contact_by_email(recp.email_address).await;
+                        let contact = contact_service.get_contact_by_email(recp.email_address.clone()).await;
 
                         let new_bounce = CreateBounceLogRequest {
                             contact_id: contact.unwrap().id,
@@ -119,7 +133,7 @@ pub async fn handle_sns_notification (
                             kind: bounce.bounce_type.clone(),
                             campaign_id: None,
                             reason: bounce.bounce_sub_type.clone(),
-                            mail_id: sns_event.mail.mail_id.clone(),
+                            mail_id: mail_id.clone(),
                         };
 
                         // Add the bounce to the DB
@@ -128,10 +142,13 @@ pub async fn handle_sns_notification (
                 }
             }
             "Delivery" => {
-                if let Some(delivery) = sns_event.delivery {
-                    let status = MailStatus::Sent;
+                if let Some(delivery) = sns_event.delivery.as_ref() {
+                    let status = MailStatus::Delivered;
 
-                    let _ = mail_service.update_mail_status(sns_event.mail.mail_id, status.as_str()).await;
+                    let mail_id = search_header_from_header_list(&sns_event, "mailId")
+                    .ok_or_else(|| AppError::NotFoundError(Some("mailId not found in SNS event".to_string())))?;
+
+                    let _ = mail_service.update_mail_status(mail_id, status.as_str()).await;
                 }
             }
             _ => {
diff --git a/backend/src/handlers/campaign.rs b/backend/src/handlers/campaign.rs
index 550ca4c..7158e07 100644
--- a/backend/src/handlers/campaign.rs
+++ b/backend/src/handlers/campaign.rs
@@ -1,5 +1,6 @@
 use uuid::Uuid;
 use crate::error::AppError;
+use crate::models::campaign::AddMailToQueueResponse;
 use crate::{models::{campaign::
     {
     CampaignSendResponse, CreateCampaignRequest, CreateCampaignResponse, DeleteCampaignResponse, ExtendedCreateCampaignRequest, GetCampaignResponse, UpdateCampaignRequest, UpdateCampaignResponse 
@@ -122,7 +123,7 @@ pub async fn delete_campaign(
 )]
 pub async fn send_campaign_email(
     Path(campaign_id): Path<String>
-) -> Result<Json<CampaignSendResponse>, AppError> {
+) -> Result<Json<AddMailToQueueResponse>, AppError> {
     let uuid_id = Uuid::parse_str(&campaign_id)?;
     let result = campaign_service::send_campaign_email(uuid_id).await?;
 
diff --git a/backend/src/handlers/contact.rs b/backend/src/handlers/contact.rs
index dad2f00..6e5ec9f 100644
--- a/backend/src/handlers/contact.rs
+++ b/backend/src/handlers/contact.rs
@@ -259,5 +259,8 @@ pub async fn get_mails_by_contact_id(
         clicks: mail.clicks,
         status: mail.status,
         status_reason: mail.reason,
+        scheduled_at: mail.scheduled_at,
+        attempts: mail.attempts,
+        last_error: mail.last_error,
     }).collect()))
 }
\ No newline at end of file
diff --git a/backend/src/handlers/mail_handler.rs b/backend/src/handlers/mail_handler.rs
index 015e4fb..c343818 100644
--- a/backend/src/handlers/mail_handler.rs
+++ b/backend/src/handlers/mail_handler.rs
@@ -1,10 +1,11 @@
 use crate::models::mail::{
     CreateMailRequest, CreateMailResponse, DeleteMailResponse, GetMailResponse, MailQuery, UpdateMailRequest, UpdateMailResponse
 };
-use crate::services::mail_service as mail_service;
+use crate::services::mail_service::{MailService, MailServiceTrait};
 
+use std::sync::Arc;
 use axum::{
-    extract:: { Path, Query }, Json
+    extract:: { Extension, Path, Query }, Json
 };
 use crate::error::AppError;
 
@@ -17,9 +18,10 @@ use crate::error::AppError;
     )
 )]
 pub async fn add_mail(
+    Extension(mail_service): Extension<Arc<MailService>>,
     Json(payload): Json<CreateMailRequest>,
 ) -> Result<Json<Vec<CreateMailResponse>>, AppError> {
-    let created_mail = mail_service::create_mail(payload).await?;
+    let created_mail = mail_service.create_mail(payload).await?;
 
     let mut responses = Vec::new();
 
@@ -48,9 +50,10 @@ pub async fn add_mail(
     )
 )]
 pub async fn get_all_mails(
+    Extension(mail_service): Extension<Arc<MailService>>,
     query: Query<MailQuery>
 ) -> Result<Json<Vec<GetMailResponse>>, AppError> {
-    let all_mails = mail_service::get_all_mails(
+    let all_mails = mail_service.get_all_mails(
         query.campaign_ids,
         query.from,
         query.to
@@ -74,6 +77,9 @@ pub async fn get_all_mails(
             status: mail.status.clone(),
             status_reason: mail.reason.clone(),
             server_id: mail.server_id.clone(),
+            scheduled_at: mail.scheduled_at,
+            attempts: mail.attempts,
+            last_error: mail.last_error.clone(),
         });
     });
     Ok(Json(responses))
@@ -89,10 +95,11 @@ pub async fn get_all_mails(
     )
 )]
 pub async fn update_mail(
+    Extension(mail_service): Extension<Arc<MailService>>,
     Path(mail_id): Path<String>,
     Json(payload): Json<UpdateMailRequest>,
 ) -> Result<Json<UpdateMailResponse>, AppError> {
-    let updated_mail = mail_service::update_mail(mail_id, payload).await?;
+    let updated_mail = mail_service.update_mail(mail_id, payload).await?;
 
     Ok(Json(updated_mail))
 }
@@ -106,9 +113,10 @@ pub async fn update_mail(
     )
 )]
 pub async fn delete_mail(
+    Extension(mail_service): Extension<Arc<MailService>>,
     Path(mail_id): Path<String>,
 ) -> Result<Json<DeleteMailResponse>, AppError> {
-    let deleted_mail = mail_service::delete_mail(mail_id).await?;
+    let deleted_mail = mail_service.delete_mail(mail_id).await?;
 
     Ok(Json(deleted_mail))
 }
\ No newline at end of file
diff --git a/backend/src/handlers/template.rs b/backend/src/handlers/template.rs
index 3114310..e034266 100644
--- a/backend/src/handlers/template.rs
+++ b/backend/src/handlers/template.rs
@@ -1,3 +1,4 @@
+use std::sync::Arc;
 use crate::error::AppError;
 use crate::models::mail::CreateMailRequest;
 use crate::models::template::{ CreateTemplateRequest, CreateTemplateResponse, DeleteTemplateResponse, GetTemplateResponse, ParseMjml2HtmlRequest, ParseMjml2HtmlResponse, SendMailRequest, SendMailResponse, TemplateResponse, UpdateTemplateRequest, UpdateTemplateResponse };
@@ -5,8 +6,9 @@ use serde_json::Value;
 use uuid::Uuid;
 
 use axum::{
-    extract:: Path, Json, http::StatusCode
+    extract:: Path, Json, http::StatusCode, Extension
 };
+use crate::services::mail_service::MailService;
 
 use crate::services::template_service;
 use crate::handlers::mail_handler as mail_handler;
@@ -140,6 +142,7 @@ pub async fn delete_template(
     )
 )]
 pub async fn send_templated_email(
+    Extension(mail_service): Extension<Arc<MailService>>,
     Path(template_id): Path<String>,
     Json(payload): Json<SendMailRequest>
 ) -> Result<Json<SendMailResponse>, AppError> {
@@ -161,11 +164,11 @@ pub async fn send_templated_email(
         template_id: Some(send_templated_email_response.id),
         campaign_id: None,
         sent_at: send_templated_email_response.sent_at,
-        status: "pending".to_string(),
+        status: "queued".to_string(),
         server_id: None,
     };
 
-    let _ = mail_handler::add_mail(Json(payload)).await;
+    let _ = mail_handler::add_mail(Extension(mail_service), Json(payload)).await;
 
     Ok(Json(send_templated_email_response))
 }
diff --git a/backend/src/lib.rs b/backend/src/lib.rs
index 5070616..5ea807a 100644
--- a/backend/src/lib.rs
+++ b/backend/src/lib.rs
@@ -78,6 +78,7 @@ pub mod utils {
     pub mod email_utils;
     pub mod mjml_parser;
     pub mod server_utils;
+    pub mod bounce_logs;
 }
 pub mod middleware;
 
diff --git a/backend/src/main.rs b/backend/src/main.rs
index 2d93754..5c9133b 100644
--- a/backend/src/main.rs
+++ b/backend/src/main.rs
@@ -4,7 +4,10 @@ use axum::middleware;
 use axum::response::Response;
 use axum::BoxError;
 use backend::error::AppError;
+use backend::repositories::mail_repository;
 use backend::route::create_router;
+use backend::services::mail_service::{self, MailServiceTrait};
+use backend::servers::{ servers_repo, servers_services };
 use diesel::PgConnection;
 use diesel::Connection; // Import the Connection trait
 use diesel_migrations::{embed_migrations, EmbeddedMigrations, MigrationHarness};
@@ -16,7 +19,7 @@ use axum::http::{
 };
 use tower_http::cors::CorsLayer;
 use std::convert::Infallible;
-use std::{env, net::SocketAddr};
+use std::{env, net::SocketAddr, sync::Arc};
 use backend::middleware::error_handling_middleware;
 
 pub const MIGRATIONS: EmbeddedMigrations = embed_migrations!("./migrations");
@@ -52,6 +55,20 @@ async fn main() {
         .layer(cors)
         .layer(middleware::from_fn(error_handling_middleware));
 
+    // Instantiate the server service and repository one time, and inject it to the process_mails background process...
+    let server_repo = Arc::new(servers_repo::ServerRepoImpl);
+    let server_service = servers_services::ServerService::new(server_repo);
+
+    let mail_repo = Arc::new(mail_repository::MailRepositoryImpl);
+    let mail_service = mail_service::MailService::new(mail_repo);
+
+    // Worker for processing mails...
+    tokio::spawn(async move {
+        if let Err(err) = mail_service.process_mails(server_service.into()).await.map_err(|err| AppError::InternalServerError(Some(format!("Mail worker error: {:?}", err.to_string())))) {
+            eprintln!("Error occurred in mail worker: {:?}", err);
+        }
+    });
+
     // Address configuration
     let addr = env::var("SERVER_ADDRESS").unwrap_or_else(|_| "0.0.0.0:8000".to_string());
     let addr: SocketAddr = addr.parse().expect("Invalid server address");
diff --git a/backend/src/models/bounce_logs.rs b/backend/src/models/bounce_logs.rs
index e5a714a..1413d4d 100644
--- a/backend/src/models/bounce_logs.rs
+++ b/backend/src/models/bounce_logs.rs
@@ -83,6 +83,12 @@ pub struct SnsNotification {
 
 }
 
+#[derive(Debug, Serialize, Deserialize, Clone, ToSchema)]
+pub struct Header {
+    pub name: String,
+    pub value: String,
+}
+
 #[derive(Debug, Deserialize, Serialize, Clone, ToSchema)]
 pub struct Message {
     #[serde(rename = "notificationType")]
@@ -92,7 +98,7 @@ pub struct Message {
     pub bounce: Option<BounceDetails>,
     pub delivery: Option<DeliveryDetails>,
     pub open: Option<OpenDetails>,
-    pub mail: MailDetails,
+    pub mail: MailDetails
 }
 
 #[derive(Debug, Deserialize, Serialize, Clone, ToSchema)]
@@ -119,6 +125,7 @@ pub struct MailDetails {
     pub destination: Vec<String>,
     #[serde(rename = "messageId")]
     pub mail_id: String,
+    pub headers: Vec<Header>
 }
 
 #[derive(Debug, Deserialize, Serialize, Clone, ToSchema)]
diff --git a/backend/src/models/campaign.rs b/backend/src/models/campaign.rs
index 5f963a4..ec9cd0d 100644
--- a/backend/src/models/campaign.rs
+++ b/backend/src/models/campaign.rs
@@ -1,8 +1,9 @@
+use axum::http::status::StatusCode;
 use chrono::{ DateTime, NaiveDateTime, Utc };
 use serde_json::Value;
 use serde::{ Serialize, Deserialize };
 use utoipa::{openapi::schema, ToSchema};
-use diesel::prelude::*;
+use diesel::{prelude::*, sql_types::Integer};
 use uuid::Uuid;
 use crate::models::list::ListResponse;
 
@@ -144,3 +145,10 @@ pub struct CampaignSendResponse {
     pub total_recipients: usize,
     pub status: String,
 }
+
+#[derive(Debug, Default, Serialize, Deserialize, ToSchema)]
+pub struct AddMailToQueueResponse {
+    #[schema(value_type = u16, example = 200)]
+    pub status: u16,
+    pub message: String,
+}
\ No newline at end of file
diff --git a/backend/src/models/mail.rs b/backend/src/models/mail.rs
index ac9b4f5..208cea5 100644
--- a/backend/src/models/mail.rs
+++ b/backend/src/models/mail.rs
@@ -4,6 +4,7 @@ use utoipa::ToSchema;
 use diesel::{pg::Pg, prelude::*};
 use uuid::Uuid;
 
+
 #[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
 
 enum MailStatus {
@@ -27,6 +28,9 @@ pub struct Mail {
     pub open: Option<DateTime<Utc>>,
     pub clicks: i32,
     pub server_id: Option<Uuid>,
+    pub scheduled_at: DateTime<Utc>,
+    pub attempts: i32,
+    pub last_error: Option<String>,
 }
 
 #[derive(Queryable, QueryableByName, ToSchema )]
@@ -62,6 +66,15 @@ pub struct MailWithDetails {
     #[diesel(sql_type = diesel::sql_types::Integer)]
     pub clicks: i32,
 
+    #[schema(value_type = String, example = "2023-01-01T00:00:00Z")]
+    pub scheduled_at: DateTime<Utc>,
+
+    #[diesel(sql_type = diesel::sql_types::Integer)]
+    pub attempts: i32,
+
+    #[diesel(sql_type = diesel::sql_types::Nullable<diesel::sql_types::Text>)]
+    pub last_error: Option<String>,
+
     #[diesel(sql_type = diesel::sql_types::Text)]
     pub email: String,  // This comes from contacts.email
 
@@ -95,6 +108,11 @@ pub struct GetMailResponse {
     pub clicks: i32,
     pub status: String,
     pub status_reason: Option<String>,
+
+    #[schema(value_type = String, example = "2023-01-01T00:00:00Z")]
+    pub scheduled_at: DateTime<Utc>,
+    pub attempts: i32,
+    pub last_error: Option<String>,
 }
 
 #[derive(Debug, Default, Serialize, Deserialize, ToSchema, Clone, PartialEq, Insertable)]
@@ -182,6 +200,11 @@ pub struct UpdateMailRequest {
     #[schema(value_type = String, example = "2023-01-01T00:00:00Z")]
     pub open: Option<DateTime<Utc>>,
     pub clicks: Option<i32>,
+    
+    #[schema(value_type = String, example = "2023-01-01T00:00:00Z")]
+    pub scheduled_at: DateTime<Utc>,
+    pub attempts: i32,
+    pub last_error: Option<String>,
 }
 
 #[derive(Debug, Serialize, Deserialize, ToSchema)]
@@ -203,6 +226,29 @@ pub struct UpdateMailResponse {
     #[schema(value_type = String, example = "2023-01-01T00:00:00Z")]
     pub open: Option<DateTime<Utc>>,
     pub clicks: i32,
+
+    #[schema(value_type = String, example = "2023-01-01T00:00:00Z")]
+    pub scheduled_at: DateTime<Utc>,
+    pub attempts: i32,
+    pub last_error: Option<String>,
+}
+
+impl From<Mail> for UpdateMailResponse {
+    fn from(mail: Mail) -> Self {
+        Self {
+            id: mail.id,
+            mail_message: mail.mail_message,
+            template_id: mail.template_id,
+            campaign_id: mail.campaign_id,
+            status: Some(mail.status),
+            updated_at: chrono::Utc::now(),
+            open: mail.open,
+            clicks: mail.clicks,
+            scheduled_at: mail.scheduled_at,
+            attempts: mail.attempts,
+            last_error: mail.last_error,
+        }
+    }
 }
 
 #[derive(Debug, Serialize, Deserialize, ToSchema)]
diff --git a/backend/src/repositories/mail_repository.rs b/backend/src/repositories/mail_repository.rs
index 692907f..06d8286 100644
--- a/backend/src/repositories/mail_repository.rs
+++ b/backend/src/repositories/mail_repository.rs
@@ -28,6 +28,7 @@ pub trait MailRepository {
     async fn delete_mail(&self, mail_id: String) -> Result<Mail, diesel::result::Error>;
     async fn increment_mail_clicks(&self, mail_id: String) -> Result<Mail, diesel::result::Error>;
     async fn get_mails_by_contact(&self, c_id: Uuid) -> Result<Vec<MailWithDetails>, diesel::result::Error>;
+    async fn get_queued_mails(&self) -> Result<Vec<MailWithDetails>, diesel::result::Error>;
 }
 
 pub struct MailRepositoryImpl;
@@ -59,6 +60,9 @@ impl MailRepository for MailRepositoryImpl {
                 status,
                 open,
                 clicks,
+                scheduled_at,
+                attempts,
+                last_error,
                 contacts_dsl::email,
                 bounce_logs_dsl::reason.nullable(),
             ))
@@ -136,6 +140,9 @@ impl MailRepository for MailRepositoryImpl {
                 status,
                 open,
                 clicks,
+                scheduled_at,
+                attempts,
+                last_error,
                 contacts_dsl::email,
                 bounce_logs_dsl::reason.nullable()
             ))
@@ -143,4 +150,31 @@ impl MailRepository for MailRepositoryImpl {
             .order(sent_at.desc())
             .load::<MailWithDetails>(&mut conn)
     }
+
+    async fn get_queued_mails(&self) -> Result<Vec<MailWithDetails>, diesel::result::Error> {
+        let mut conn = get_connection_pool().await;
+
+        mails
+            .inner_join(contacts_dsl::contacts.on(contact_id.eq(contacts_dsl::id)))
+            .left_outer_join(bounce_logs_dsl::bounce_logs.on(id.eq(bounce_logs_dsl::mail_id)))
+            .select((
+                id,
+                mail_message,
+                template_id,
+                campaign_id,
+                server_id,
+                sent_at,
+                status,
+                open,
+                clicks,
+                scheduled_at,
+                attempts,
+                last_error,
+                contacts_dsl::email,
+                bounce_logs_dsl::reason.nullable(),
+            ))
+            .filter(status.eq("queued"))
+            .order(sent_at.asc())   // Order by sent_at ascending here...
+            .load::<MailWithDetails>(&mut conn)
+    }
 }
\ No newline at end of file
diff --git a/backend/src/routes/bounce_logs_route.rs b/backend/src/routes/bounce_logs_route.rs
index 71fba63..05bb148 100644
--- a/backend/src/routes/bounce_logs_route.rs
+++ b/backend/src/routes/bounce_logs_route.rs
@@ -1,18 +1,27 @@
+use std::sync::Arc;
 use axum::{
     routing::{
         get,
         post,
         delete
-    }, Router };
+    }, Router, Extension };
 
 use crate::handlers::bounce_logs_handler::{
     delete_bounce, get_all_bounces, get_bounces_by_contact_id, handle_sns_notification
 };
 
+use crate::services::mail_service;
+use crate::repositories::mail_repository;
+
+
 pub fn bounce_logs_routes() -> Router {
+    let mail_repo = Arc::new(mail_repository::MailRepositoryImpl);
+    let mail_service = mail_service::MailService::new(mail_repo);
+
     Router::new()
         .route("/sns/bounce", post(handle_sns_notification))
         .route("/", get(get_all_bounces))
         .route("/contacts/{contactId}", get(get_bounces_by_contact_id))
         .route("/{bounceId}", delete(delete_bounce))
+        .layer(Extension(Arc::new(mail_service)))
 }
\ No newline at end of file
diff --git a/backend/src/routes/mail.rs b/backend/src/routes/mail.rs
index 7c19d3f..2eeb0bf 100644
--- a/backend/src/routes/mail.rs
+++ b/backend/src/routes/mail.rs
@@ -1,22 +1,25 @@
+use std::sync::Arc;
+
 use axum::{
     routing::{
-        get,
-        post,
-        patch,
-        delete
-    }, Router };
+        delete, get, patch, post
+    }, Extension, Router };
 
 use crate::handlers::mail_handler::{
-    add_mail,
-    get_all_mails,
-    update_mail,
-    delete_mail
+    add_mail, delete_mail, get_all_mails, update_mail
 };
 
+use crate::services::mail_service as service;
+use crate::repositories::mail_repository;
+
 pub fn mail_routes() -> Router {
+    let mail_repo = Arc::new(mail_repository::MailRepositoryImpl);
+    let mail_service = service::MailService::new(mail_repo);
+
     Router::new()
         .route("/", post(add_mail))
         .route("/", get(get_all_mails))
         .route("/{mailId}", patch(update_mail))
         .route("/{mailId}", delete(delete_mail))
+        .layer(Extension(Arc::new(mail_service)))
 }
\ No newline at end of file
diff --git a/backend/src/routes/template.rs b/backend/src/routes/template.rs
index 29e8068..19a293a 100644
--- a/backend/src/routes/template.rs
+++ b/backend/src/routes/template.rs
@@ -1,17 +1,22 @@
+use std::sync::Arc;
+
 use axum::{
     routing::{
-        get,
-        post,
-        patch,
-        delete
-    }, Router };
+        delete, get, patch, post
+    }, Extension, Router };
 
 use crate::handlers::template::{
     delete_template, get_templates, get_templates_by_id, create_template, update_template, send_templated_email, parse_mjml_to_html
 };
 
+use crate::services::mail_service;
+use crate::repositories::mail_repository;
+
 
 pub fn template_routes() -> Router {
+    let mail_repo = Arc::new(mail_repository::MailRepositoryImpl);
+    let mail_service = mail_service::MailService::new(mail_repo);
+
     Router::new()
         .route("/{templateId}", get(get_templates_by_id))
         .route("/", get(get_templates))
@@ -20,4 +25,5 @@ pub fn template_routes() -> Router {
         .route("/{templateId}", delete(delete_template))
         .route("/{templateId}/send", post(send_templated_email))
         .route("/parse-mjml", post(parse_mjml_to_html))
+        .layer(Extension(Arc::new(mail_service)))
 }
\ No newline at end of file
diff --git a/backend/src/schema.rs b/backend/src/schema.rs
index 178a68e..c41f712 100644
--- a/backend/src/schema.rs
+++ b/backend/src/schema.rs
@@ -100,6 +100,9 @@ diesel::table! {
         open -> Nullable<Timestamptz>,
         clicks -> Int4,
         server_id -> Nullable<Uuid>,
+        scheduled_at -> Timestamptz,
+        attempts -> Int4,
+        last_error -> Nullable<Text>,
     }
 }
 
@@ -131,6 +134,7 @@ diesel::table! {
         created_at -> Timestamptz,
         updated_at -> Timestamptz,
         default_from_email -> Varchar,
+        rate_limit -> Int4,
     }
 }
 
diff --git a/backend/src/servers/servers_handler.rs b/backend/src/servers/servers_handler.rs
index c730305..542e03d 100644
--- a/backend/src/servers/servers_handler.rs
+++ b/backend/src/servers/servers_handler.rs
@@ -9,6 +9,9 @@ use std::sync::Arc;
 use uuid::Uuid;
 
 use crate::servers::servers_services::{ServerServiceTrait, ServerService};
+use crate::services::mail_service::MailService;
+use crate::utils::server_utils::secure_server_response;
+
 
 use serde::Serialize;
 
@@ -197,6 +200,9 @@ pub async fn get_mails_from_server(
         status_reason: mail.reason,
         mail_message: mail.mail_message,
         campaign_id: mail.campaign_id,
+        scheduled_at: mail.scheduled_at,
+        attempts: mail.attempts,
+        last_error: mail.last_error,
     }).collect();
 
     Ok(Json(mails_response))
diff --git a/backend/src/servers/servers_model.rs b/backend/src/servers/servers_model.rs
index 3d79afe..e8314bd 100644
--- a/backend/src/servers/servers_model.rs
+++ b/backend/src/servers/servers_model.rs
@@ -52,6 +52,7 @@ pub struct Server {
     pub created_at: DateTime<Utc>,
     pub updated_at: DateTime<Utc>,
     pub default_from_email: String,
+    pub rate_limit: i32
 }
 // Create DTOs
 #[derive(Debug, Default, Serialize, Deserialize, ToSchema, Clone, PartialEq)]
@@ -86,6 +87,9 @@ pub struct ServerRequest {
     
     #[schema(example = "from.email@test.io")]
     pub default_from_email: String,
+
+    #[schema(example = 30)]
+    pub rate_limit: i32
 }
 
 // Get DTO
@@ -111,11 +115,13 @@ pub struct ServerResponse {
     pub updated_at: DateTime<Utc>,
     #[schema(example = "from.email@test.io")]
     pub default_from_email: String,
+    #[schema(example = 30)]
+    pub rate_limit: i32
 }
 
 impl From<Server> for ServerResponse {
     fn from(server: Server) -> Self {
-        let safe_aws = server.aws_credentials.map(|creds| secure_server_response(creds));
+        // let safe_aws = server.aws_credentials.map(|creds| secure_server_response(creds));
 
         Self {
             id: server.id,
@@ -127,10 +133,11 @@ impl From<Server> for ServerResponse {
             tls_type: server.tls_type,
             port: server.port,
             server_type: server.server_type,
-            aws_credentials: safe_aws,
+            aws_credentials: server.aws_credentials,
             created_at: server.created_at,
             updated_at: server.updated_at,
             default_from_email: server.default_from_email,
+            rate_limit: server.rate_limit,
         }
     }
 }
diff --git a/backend/src/servers/servers_repo.rs b/backend/src/servers/servers_repo.rs
index 2b3f939..1d56ae4 100644
--- a/backend/src/servers/servers_repo.rs
+++ b/backend/src/servers/servers_repo.rs
@@ -55,6 +55,7 @@ impl ServerRepo for ServerRepoImpl {
                 created_at,
                 updated_at,
                 default_from_email,
+                rate_limit,
             ))
             .load::<Server>(&mut conn)
     }
@@ -78,6 +79,7 @@ impl ServerRepo for ServerRepoImpl {
                 aws_credentials.eq(&payload.aws_credentials),
                 port.eq(&payload.port),
                 default_from_email.eq(&payload.default_from_email),
+                rate_limit.eq(&payload.rate_limit),
             ))
             .get_result(&mut conn)
     }
@@ -118,6 +120,9 @@ impl ServerRepo for ServerRepoImpl {
                 status,
                 open,
                 clicks,
+                scheduled_at,
+                attempts,
+                last_error,
                 contacts_dsl::email,
                 bounce_logs_dsl::reason.nullable(),
             ))
diff --git a/backend/src/servers/servers_routes.rs b/backend/src/servers/servers_routes.rs
index 90773e4..e2f8716 100644
--- a/backend/src/servers/servers_routes.rs
+++ b/backend/src/servers/servers_routes.rs
@@ -10,16 +10,9 @@ use::axum::{
     }, Router
 };
 
-use crate::servers::servers_handler::{
-    create_server, 
-    get_servers, 
-    get_server_by_id, 
-    delete_server,
-    update_server, 
-    check_credentials,
-    send_mail_from_server,
-    get_mails_from_server
-};
+use crate::{repositories::mail_repository, servers::servers_handler::{
+    check_credentials, create_server, delete_server, get_mails_from_server, get_server_by_id, get_servers, send_mail_from_server, update_server
+}, services::mail_service};
 
 use crate::servers::servers_services;
 use crate::servers::servers_repo;
diff --git a/backend/src/servers/servers_services.rs b/backend/src/servers/servers_services.rs
index 9243116..34e0aaa 100644
--- a/backend/src/servers/servers_services.rs
+++ b/backend/src/servers/servers_services.rs
@@ -1,4 +1,4 @@
-use crate::{error::AppError, schema::sql_types::TlsType, models::contact::Contact, servers::{servers_repo::{ServerRepo, ServerRepoImpl}, servers_services}};
+use crate::{error::AppError, models::contact::Contact, schema::sql_types::TlsType, servers::{servers_repo::{ServerRepo, ServerRepoImpl}, servers_services}, services::mail_service::MailServiceTrait};
 
 use uuid::Uuid;
 use std::sync::Arc;
@@ -6,6 +6,7 @@ use axum::extract::Extension;
 use axum::http::StatusCode;
 use crate::models::mail::{CreateMailRequest, MailWithDetails};
 use crate::services::mail_service;
+use crate::repositories::mail_repository::{ MailRepository, MailRepositoryImpl };
 use crate::servers::servers_model::{ Server, ServerRequest, SendMailFromServerResponse, ServerTypeEnum };
 use crate::services::template_service::{get_template_by_id, send_templated_email};
 use crate::models::template::SendMailRequest;
@@ -19,8 +20,10 @@ use super::servers_model::TlsTypeEnum;
 use lettre::{
     message::{Message, MultiPart, SinglePart}, transport::smtp::{authentication::Credentials, client::{Tls, TlsParameters}}, SmtpTransport, Transport
 };
+use mockall::{ automock, predicate::* };
 
 
+#[automock]
 #[async_trait]
 pub trait ServerServiceTrait {
     async fn create_server(&self, payload: ServerRequest) -> Result<Server, AppError>;
@@ -42,6 +45,7 @@ pub trait ServerServiceTrait {
     async fn send_mail_from_server(&self, server_id: &str, template_id: Uuid, receiver: String) -> Result<SendMailFromServerResponse, AppError>;
     async fn get_mails_by_server_id(&self, server_id: Uuid) -> Result<Vec<MailWithDetails>, AppError>;
 }
+
 #[derive(Clone)]
 pub struct ServerService {
     repository: Arc<dyn ServerRepo + Send + Sync>
@@ -228,6 +232,9 @@ impl ServerServiceTrait for ServerService {
         let receivers = receiver.split(",").map(|s| s.to_string()).collect::<Vec<String>>();
         let mut mail_send_ids: Vec<Uuid> = Vec::new();
 
+        let mail_repo = Arc::new(MailRepositoryImpl);
+        let mail_service = mail_service::MailService::new(mail_repo);
+
         match server.server_type {
             // send mail using the AWS credentials...
             ServerTypeEnum::AWS => {
@@ -255,17 +262,18 @@ impl ServerServiceTrait for ServerService {
                     sent_at: chrono::Utc::now(),
                     status: "sent".to_string(),
                 };
-            
-                mail_service::create_mail(new_mail).await.map_err(|err| {
+
+                mail_service.create_mail(new_mail).await.map_err(|err| {
                     AppError::InternalServerError(Some(format!("Failed to create mail: {}", err)))
                 })?;
+            
 
                 Ok(SendMailFromServerResponse {
                     id: mail_send_uuid,
                     template_id,
                     server_id: server.id,
                     mail_send_ids: vec![mail_send_uuid],
-                    status: "pending".to_string(),
+                    status: "queued".to_string(),
                     sent_at: chrono::Utc::now(),
                 }) 
             },
@@ -315,10 +323,10 @@ impl ServerServiceTrait for ServerService {
                         campaign_id: None,
                         server_id: Some(server.id),
                         sent_at: chrono::Utc::now(),
-                        status: "pending".to_string(),
+                        status: "queued".to_string(),
                     };
                 
-                    mail_service::create_mail(new_mail).await.map_err(|err| {
+                    mail_service.create_mail(new_mail).await.map_err(|err| {
                         AppError::InternalServerError(Some(format!("Failed to create mail: {}", err)))
                     })?;
 
diff --git a/backend/src/services/aws_service.rs b/backend/src/services/aws_service.rs
index 675351f..0a60014 100644
--- a/backend/src/services/aws_service.rs
+++ b/backend/src/services/aws_service.rs
@@ -1,4 +1,4 @@
-use aws_sdk_sesv2::{error::SdkError, operation::send_email::SendEmailOutput, types::{Body, Content, Destination, EmailContent, Message, SuppressionListReason }, Client };
+use aws_sdk_sesv2::{error::SdkError, operation::send_email::SendEmailOutput, types::{Body, Content, Destination, EmailContent, Message, MessageHeader, SuppressionListReason }, Client };
 use aws_config::{BehaviorVersion, Region};
 
 use std::{env, error::Error, sync::Arc};
@@ -46,7 +46,8 @@ pub async fn send_mail(
     cc: Option<Vec<String>>,
     bcc: Option<Vec<String>>, 
     subject: &str, 
-    html_data: &str
+    html_data: &str,
+    mail_id: Option<&str>
 ) -> Result<SendEmailOutput, SdkError<aws_sdk_sesv2::operation::send_email::SendEmailError>> {
     let mut destination = Destination::builder().build();
     destination.to_addresses = Some(to.clone());
@@ -92,16 +93,26 @@ pub async fn send_mail(
 
     let msg = Message::builder()
         .subject(subject_content)
+        .set_headers(Some(vec![
+            MessageHeader::builder()
+                .name("mailId")
+                .value(mail_id.unwrap())
+                .build()?
+        ]))
         .body(body)
         .build();
 
     let email_content = EmailContent::builder().simple(msg).build();
 
+    let configuration_set_name = env::var("AWS_SES_CONFIGURATION_SET_NAME")
+    .expect("You must have env of configuration set name for open and click rates tracking named: AWS_SES_CONFIGURATION_SET_NAME");
+
     let result = client
         .send_email()
         .from_email_address(from)
         .destination(destination)
         .content(email_content)
+        .set_configuration_set_name(Some(configuration_set_name))
         .send()
         .await;
 
diff --git a/backend/src/services/campaign_service.rs b/backend/src/services/campaign_service.rs
index 66f3411..460231f 100644
--- a/backend/src/services/campaign_service.rs
+++ b/backend/src/services/campaign_service.rs
@@ -1,4 +1,4 @@
-use crate::{error::AppError, models::{campaign::{CampaignSendResponse, DeleteCampaignResponse, GetCampaignResponse, UpdateCampaignRequest, UpdateCampaignResponse}, campaign_lists::NewListInCampaign, mail::CreateMailRequest}, repositories::{campaign::{self, CampaginRepositoryImpl, CampaignRepository}, campaign_lists_repo::{CampaignListRepository, CampaignListRepositoryImpl}, list_contact_repo::ListContactRepositoryImpl, mail_repository::MailRepositoryImpl},servers::{servers_handler::get_server_by_id, servers_model::{Server, ServerTypeEnum}, servers_repo::{self, ServerRepoImpl}, servers_services::{self, ServerService, ServerServiceTrait}}, utils::contact_lists_functions::{get_unique_contacts_from_campaign, populate_contact_template}};
+use crate::{error::AppError, models::{campaign::{CampaignSendResponse, DeleteCampaignResponse, GetCampaignResponse, UpdateCampaignRequest, UpdateCampaignResponse, AddMailToQueueResponse}, campaign_lists::NewListInCampaign, mail::CreateMailRequest}, repositories::{campaign::{self, CampaginRepositoryImpl, CampaignRepository}, campaign_lists_repo::{CampaignListRepository, CampaignListRepositoryImpl}, list_contact_repo::ListContactRepositoryImpl, mail_repository::{ MailRepository, MailRepositoryImpl}}, servers::{servers_handler::get_server_by_id, servers_model::{Server, ServerTypeEnum}, servers_repo::{self, ServerRepoImpl}, servers_services::{self, ServerService, ServerServiceTrait}}, utils::contact_lists_functions::{get_unique_contacts_from_campaign, populate_contact_template}};
 use uuid::Uuid;
 use std::{collections::HashSet, sync::Arc, env};
 use axum::http::StatusCode;
@@ -13,7 +13,7 @@ use aws_sdk_sesv2::types::{builders::{BodyBuilder, ContentBuilder}, Body, Conten
 use crate::services::{aws_service, list_service::ListContactService, template_service::get_template_by_id};
 use anyhow::{anyhow, Result};
 
-use super::{aws_service::create_aws_client_db, campaign_sender_service::get_campaign_sender_by_id, mail_service::MailService };
+use super::{aws_service::create_aws_client_db, campaign_sender_service::get_campaign_sender_by_id, mail_service::{MailService, MailServiceTrait} };
 use crate::services::mail_service as mail_service;
 
 
@@ -241,10 +241,10 @@ pub async fn delete_campaign(campaign_id: Uuid)->Result<DeleteCampaignResponse,
     })
 }
 
+/// a function that queues the email for sending...
 pub async fn send_campaign_email(
     campaign_id: Uuid,
-) -> Result<CampaignSendResponse, AppError> {
-
+) -> Result<AddMailToQueueResponse, AppError> {
   let campaign = get_campaign_by_id(campaign_id).await?;
   let campaign_sender_id = campaign
     .campaign_senders
@@ -260,18 +260,12 @@ pub async fn send_campaign_email(
 
   let server = server_service.get_server_by_id(server_id.as_str()).await?;
 
-
-  match server.server_type {
-    ServerTypeEnum::AWS => {
-        let result = send_campaign_email_aws(campaign_id).await?;
-        Ok(result)
-    }, 
-    ServerTypeEnum::SMTP => {
-        let result = send_campaign_email_smtp(campaign_id, Uuid::parse_str(&server_id).unwrap()).await?;
-        Ok(result)
-    } 
-  }
-
+    // modified to add the mails to queue rather than directly sending them...
+  let _result = enqueue_email(campaign_id, server.id).await?;
+  return Ok(AddMailToQueueResponse {
+      status: StatusCode::OK.into(),
+      message: "Campaign email sent successfully".to_string(),
+  });
 }
 
 pub async fn send_campaign_email_aws(
@@ -308,6 +302,9 @@ pub async fn send_campaign_email_aws(
     let client = aws_service::create_aws_client_db(&server_id).await;
     let request = client.list_email_identities();
 
+    let mail_repo = Arc::new(MailRepositoryImpl);
+    let mail_service = mail_service::MailService::new(mail_repo);
+
     // Send the request and await the response
     let result = request.send().await.map_err(|err| AppError::InternalServerError(Some(err.to_string())))?;
 
@@ -365,11 +362,11 @@ pub async fn send_campaign_email_aws(
             template_id: Some(Uuid::parse_str(&template.id)?),
             campaign_id: Some(campaign_id),
             sent_at: chrono::Utc::now(),
-            status: "pending".to_string(),
+            status: "queued".to_string(),
             server_id: Some(server_uuid),
         };
 
-        mail_service::create_mail(new_mail).await?;
+        mail_service.create_mail(new_mail).await?;
     }
     Ok(CampaignSendResponse {
         campaign_id: campaign_id.to_string(),
@@ -412,6 +409,9 @@ pub async fn send_campaign_email_smtp(
     let sender_email = campaign_sender_response.from_email;
     let server_service = ServerService::new(Arc::new(ServerRepoImpl));
 
+    let mail_repo = Arc::new(MailRepositoryImpl);
+    let mail_service = mail_service::MailService::new(mail_repo);
+
     for contact in contacts.clone() {
         let parsed_html = populate_contact_template(&template, &contact).await.map_err(|err| AppError::InternalServerError(Some(err.to_string())))?;
 
@@ -432,12 +432,12 @@ pub async fn send_campaign_email_smtp(
                     mail_message: parsed_html,
                     email: vec![contact.email.clone()],
                     template_id: Some(Uuid::parse_str(&template.id)?),
-                    campaign_id: Some((campaign_id)),
+                    campaign_id: Some(campaign_id),
                     sent_at: chrono::Utc::now(),
-                    status: "pending".to_string(),
+                    status: "queued".to_string(),
                     server_id: Some(server_id),
                 };
-                mail_service::create_mail(new_mail).await.map_err(|err| {
+                mail_service.create_mail(new_mail).await.map_err(|err| {
                     AppError::InternalServerError(Some(format!("Failed to create mail: {}", err)))
                 })?;
             },
@@ -454,3 +454,110 @@ pub async fn send_campaign_email_smtp(
     })
 }
 
+/// a function to send a single email to a contact with smtp server...
+pub async fn send_single_email (
+    server_type: ServerTypeEnum,
+    mail_id: String,
+    campaign_id: Uuid,
+    server_id: Uuid,
+    email: String,
+    message: String,
+    subject: String,
+) -> Result<CampaignSendResponse, AppError> {
+    let server_service = ServerService::new(Arc::new(ServerRepoImpl));
+
+    let campaign = get_campaign_by_id(campaign_id.clone())
+        .await
+        .map_err(|err| AppError::NotFoundError(Some(err.to_string())))?;
+
+    let sender_id_string = match campaign.campaign_senders {
+        Some(uuid) => uuid.to_string(),
+        None => return Err(AppError::NotFoundError(Some("Sender ID not found for campaign.".to_string()))),
+    };
+
+    let campaign_sender_response = get_campaign_sender_by_id(sender_id_string).await
+        .map_err(|err| AppError::InternalServerError(Some(err.to_string())))?;
+
+    let sender_email = campaign_sender_response.from_email;
+
+    let mail_repo = Arc::new(MailRepositoryImpl);
+    let mail_service = mail_service::MailService::new(mail_repo);
+
+    let _result = match server_type {
+        ServerTypeEnum::AWS => {
+            let client = aws_service::create_aws_client_db(&server_id.to_string()).await;
+
+            aws_service::send_mail(
+                client, 
+                &sender_email, 
+                vec![email], 
+                None, 
+                None, 
+                &subject, 
+                &message,
+                Some(&mail_id),
+            ).await.map_err(|err| AppError::InternalServerError(Some(format!("{:?}", err))))?;
+        },
+        ServerTypeEnum::SMTP => {
+            server_service.send_mail_with_smtp(
+                server_id,
+                &sender_email,
+                vec![email],
+                None,
+                None,
+                &subject,
+                &message,
+            ).await.map_err(|err| AppError::InternalServerError(Some(format!("{:?}", err))))?;
+        }
+    };
+    let mail_status = "submitted";
+
+    mail_service.update_mail_status(mail_id, mail_status).await.map_err(|err| {
+        AppError::InternalServerError(Some(format!("Failed to update mail status: {}", err)))
+    })?;
+
+    Ok(CampaignSendResponse {
+        campaign_id: campaign_id.to_string(),
+        total_recipients: 1,
+        status: mail_status.to_string(),
+    })
+}
+
+/// a function to enqueue email for sending...
+pub async fn enqueue_email(
+    campaign_id: Uuid,
+    server_id: Uuid
+) -> Result<(), AppError> {
+    let campaign = get_campaign_by_id(campaign_id.clone())
+    .await
+    .map_err(|err| AppError::NotFoundError(Some(err.to_string())))?;
+
+    let contacts = get_unique_contacts_from_campaign(campaign_id).await?;
+
+    let template = get_template_by_id(campaign.template_id.clone()).await
+    .map_err(|err| AppError::InternalServerError(Some(err.to_string())))?;
+
+    let mail_repo = Arc::new(MailRepositoryImpl);
+    let mail_service = mail_service::MailService::new(mail_repo);
+
+    for contact in contacts.clone() {
+        let parsed_html = populate_contact_template(&template, &contact).await.map_err(|err| AppError::InternalServerError(Some(err.to_string())))?;
+
+        let new_mail = CreateMailRequest {
+            id: Uuid::new_v4().to_string(),
+            mail_message: parsed_html,
+            email: vec![contact.email.clone()],
+            template_id: Some(Uuid::parse_str(&template.id)?),
+            campaign_id: Some(campaign_id),
+            sent_at: chrono::Utc::now(),
+            status: "queued".to_string(),
+            server_id: Some(server_id),
+        };
+
+        mail_service.create_mail(new_mail).await.map_err(|err| {
+            AppError::InternalServerError(Some(format!("Failed to create mail: {}", err)))
+        })?;
+    }
+
+    Ok(())
+}
\ No newline at end of file
diff --git a/backend/src/services/contact_service.rs b/backend/src/services/contact_service.rs
index 9a2e6b9..c1968ba 100644
--- a/backend/src/services/contact_service.rs
+++ b/backend/src/services/contact_service.rs
@@ -1,7 +1,6 @@
 use crate::{models::contact::{ContactList, GetContactResponsee}, repositories::contact::{self, ContactRepository, ContactRepositoryImpl}};
 use uuid::Uuid;
 use std::{collections::HashMap, sync::Arc};
-use axum::{http::StatusCode, Json};
 use crate::models::contact::{
     Contact,
     CreateContactRequest,
@@ -10,9 +9,10 @@ use crate::models::contact::{
 };
 use crate::models::mail::MailWithDetails;
 use crate::error::AppError;
-use crate::services::mail_service::get_mails_by_contact;
+use super::{list_service, mail_service::MailServiceTrait};
+use crate::repositories::mail_repository::{ MailRepository, MailRepositoryImpl };
+use crate::services::mail_service;
 
-use super::list_service;
 
 pub struct ContactService {
     repository: Arc<dyn ContactRepository + Send + Sync>
@@ -254,7 +254,10 @@ pub async fn import_contacts(
 }
 
 pub async fn get_mails_for_contact (contact_id: Uuid) -> Result<Vec<MailWithDetails>, AppError> {
-    let mails = get_mails_by_contact(contact_id).await?;
+    let mail_repo = Arc::new(MailRepositoryImpl);
+        let mail_service = mail_service::MailService::new(mail_repo);
+
+    let mails = mail_service.get_mails_by_contact(contact_id).await?;
 
     Ok(mails)
 }
\ No newline at end of file
diff --git a/backend/src/services/mail_service.rs b/backend/src/services/mail_service.rs
index 727db23..5e88d04 100644
--- a/backend/src/services/mail_service.rs
+++ b/backend/src/services/mail_service.rs
@@ -1,8 +1,10 @@
-use crate::{models::mail::{DeleteMailResponse, MailWithDetails, NewMail}, repositories::mail_repository::{ MailRepository, MailRepositoryImpl }};
+use crate::{models::mail::{DeleteMailResponse, MailWithDetails, NewMail}, repositories::mail_repository::MailRepository, services::campaign_service::send_single_email};
+use crate::servers::servers_services::{ ServerService, ServerServiceTrait };
 use crate::services::contact_service as contact_service;
 use chrono::{DateTime, Utc};
+use tokio::time::{interval, Duration};
 use uuid::Uuid;
-use std::sync::Arc;
+use std::{collections::HashMap, num::NonZeroU32, sync::Arc, time::Instant};
 use crate::models::mail::{
     Mail,
     CreateMailRequest,
@@ -10,161 +12,219 @@ use crate::models::mail::{
     UpdateMailResponse
 };
 use crate::error::AppError;
+use governor::{Quota, RateLimiter, clock::DefaultClock, state::{ InMemoryState, NotKeyed }, middleware::NoOpMiddleware};
+use crate::servers::servers_model::ServerTypeEnum;
+use async_trait::async_trait;
+use mockall::{ automock, predicate::* };
 
+
+/// a structure to hold the server state along with its rate limiter and the server_type to decide from what server (either AWS or SMTP) to send the email...
+#[derive(Debug)]
+pub struct ServerState {
+    pub limiter: RateLimiter<NotKeyed, InMemoryState, DefaultClock, NoOpMiddleware>,
+    pub server_type: ServerTypeEnum,
+}
+
+#[automock]
+#[async_trait]
+pub trait MailServiceTrait {
+    async fn create_mail(&self, payload: CreateMailRequest) -> Result<Vec<Mail>, AppError>;
+    async fn get_all_mails(&self, campaign_ids: Option<Uuid>, from: Option<DateTime<Utc>>, to: Option<DateTime<Utc>>) -> Result<Vec<MailWithDetails>, AppError>;
+    async fn update_mail(&self, mail_id: String, payload: UpdateMailRequest) -> Result<UpdateMailResponse, AppError>;
+    async fn update_mail_status(&self, mail_id: String, new_status: &str) -> Result<UpdateMailResponse, AppError>;
+    async fn delete_mail(&self, mail_id: String) -> Result<DeleteMailResponse, AppError>;
+    async fn increment_mail_clicks(&self, mail_id: String) -> Result<UpdateMailResponse, AppError>;
+    async fn get_mails_by_contact(&self, contact_id: Uuid) -> Result<Vec<MailWithDetails>, AppError>;
+    async fn fetch_queued_mails(&self) -> Result<Vec<MailWithDetails>, AppError>;
+    async fn process_mails(
+        &self,
+        server_service: Arc<ServerService>,
+    ) -> Result<(), AppError>;
+}
+
+#[derive(Clone)]
 pub struct MailService {
     repository: Arc<dyn MailRepository + Send + Sync>
 }
 
+#[automock]
 impl MailService {
     pub fn new(repository: Arc<dyn MailRepository + Send + Sync>) -> Self {
         Self { repository }
     }
+}
 
-    pub async fn create_mail(&self, payload: NewMail) -> Result<Mail, diesel::result::Error> {
-        self.repository.create_mail(payload).await
+#[async_trait]
+impl MailServiceTrait for MailService {
+    /// a function to add new mail into the record when the mail_send is triggered...
+    async fn create_mail(&self, payload: CreateMailRequest) -> Result<Vec<Mail>, AppError> {    
+        let mut responses = Vec::new(); // Vec<CreateMailResponse>;
+        for email in payload.email {
+            let contact = contact_service::get_contact_by_email(email).await?;
+
+            let new_mail = NewMail {
+                id: payload.id.clone(),
+                mail_message: payload.mail_message.clone(),
+                contact_id: contact.id,
+                template_id: payload.template_id,
+                campaign_id: payload.campaign_id,
+                server_id: payload.server_id,
+                sent_at: payload.sent_at,
+                status: payload.status.clone(),
+            };
+            let response = self.repository.create_mail(new_mail).await?;
+
+            responses.push(response);
+        }
+
+        Ok(responses)
     }
 
-    pub async fn get_all_mails(&self, campaign_ids: Option<Uuid>, from: Option<DateTime<Utc>>, to: Option<DateTime<Utc>>) -> Result<Vec<MailWithDetails>, diesel::result::Error> {
-        self.repository.get_all_mails(campaign_ids, from, to).await
-    }
+    /// a function to get all mails from the record...
+    async fn get_all_mails(
+        &self,
+        campaign_ids: Option<Uuid>,
+        from: Option<DateTime<Utc>>,
+        to: Option<DateTime<Utc>>
+    ) -> Result<Vec<MailWithDetails>, AppError> {    
+        let response = self.repository.get_all_mails(campaign_ids, from, to).await?;
 
-    pub async fn update_mail(&self, mail_id: String, payload: UpdateMailRequest) -> Result<Mail, diesel::result::Error> {
-        self.repository.update_mail(mail_id, payload).await
+        Ok(response)
     }
 
-    pub async fn update_mail_status(&self, mail_id: String, new_status: &str) -> Result<Mail, diesel::result::Error> {
-        self.repository.update_mail_status(mail_id, new_status).await
-    }
+    /// a function to update mail in the record...
+    async fn update_mail(&self, mail_id: String, payload: UpdateMailRequest) -> Result<UpdateMailResponse, AppError> {
+        let response = self.repository.update_mail(mail_id, payload).await?;
 
-    pub async fn delete_mail(&self, mail_id: String) -> Result<Mail, diesel::result::Error> {
-        self.repository.delete_mail(mail_id).await
-    }
+        let updated_mail_response: UpdateMailResponse = response.into();
 
-    pub async fn increment_mail_clicks(&self, mail_id: String) -> Result<Mail, diesel::result::Error> {
-        self.repository.increment_mail_clicks(mail_id).await
+        Ok(updated_mail_response)
     }
 
-    pub async fn get_mails_by_contact(&self, contact_id: Uuid) -> Result<Vec<MailWithDetails>, diesel::result::Error> {
-        self.repository.get_mails_by_contact(contact_id).await
-    }
-}
+    /// a function to update mail status...
+    async fn update_mail_status(&self, mail_id: String, new_status: &str) -> Result<UpdateMailResponse, AppError> {
+        let response = self.repository.update_mail_status(mail_id, new_status).await?;
+
+        let updated_mail_response: UpdateMailResponse = response.into();
 
-/// a function to add new mail into the record when the mail_send is triggered...
-pub async fn create_mail(payload: CreateMailRequest) -> Result<Vec<Mail>, AppError> {
-    let mail_repository = Arc::new(MailRepositoryImpl);
-    let mail_service = MailService::new(mail_repository);
-    
-    let mut responses = Vec::new(); // Vec<CreateMailResponse>;
-    for email in payload.email {
-        let contact = contact_service::get_contact_by_email(email).await?;
-
-        let new_mail = NewMail {
-            id: payload.id.clone(),
-            mail_message: payload.mail_message.clone(),
-            contact_id: contact.id,
-            template_id: payload.template_id,
-            campaign_id: payload.campaign_id,
-            server_id: payload.server_id,
-            sent_at: payload.sent_at,
-            status: payload.status.clone(),
-        };
-        let response = mail_service.create_mail(new_mail).await?;
-
-        responses.push(response);
+        Ok(updated_mail_response)
     }
 
-    Ok(responses)
-}
+    /// a function to delete mail from the db relation...
+    async fn delete_mail(&self, mail_id: String) -> Result<DeleteMailResponse, AppError> {
+        let response = self.repository.delete_mail(mail_id).await?;
 
-/// a function to get all mails from the record...
-pub async fn get_all_mails(
-    campaign_ids: Option<Uuid>,
-    from: Option<DateTime<Utc>>,
-    to: Option<DateTime<Utc>>
-) -> Result<Vec<MailWithDetails>, AppError> {
-    let mail_repository = Arc::new(MailRepositoryImpl);
-    let mail_service = MailService::new(mail_repository);
-    
-    let response = mail_service.get_all_mails(campaign_ids, from, to).await?;
-
-    Ok(response)
-}
+        Ok(DeleteMailResponse {
+            id: response.id,
+            status: Some(response.status),
+            contact_id: Some(response.contact_id),
+        })
+    }
 
-/// a function to update mail in the record...
-pub async fn update_mail(mail_id: String, payload: UpdateMailRequest) -> Result<UpdateMailResponse, AppError> {
-    let mail_repository = Arc::new(MailRepositoryImpl);
-    let mail_service = MailService::new(mail_repository);
-
-    let response = mail_service.update_mail(mail_id, payload).await?;
-
-    Ok(UpdateMailResponse {
-        id: response.id,
-        mail_message: response.mail_message,
-        template_id: response.template_id,
-        campaign_id: response.campaign_id,
-        status: Some(response.status),
-        updated_at: chrono::Utc::now(),
-        open: response.open,
-        clicks: response.clicks,
-    })
-}
+    async fn increment_mail_clicks(&self, mail_id: String) -> Result<UpdateMailResponse, AppError> {
+        let response = self.repository.increment_mail_clicks(mail_id).await?;
 
-/// a function to update mail status...
-pub async fn update_mail_status(mail_id: String, new_status: String) -> Result<UpdateMailResponse, AppError> {
-    let mail_repository = Arc::new(MailRepositoryImpl);
-    let mail_service = MailService::new(mail_repository);
-
-    let response = mail_service.update_mail_status(mail_id, &new_status).await?;
-
-    Ok(UpdateMailResponse {
-        id: response.id,
-        mail_message: response.mail_message,
-        template_id: response.template_id,
-        campaign_id: response.campaign_id,
-        status: Some(response.status),
-        updated_at: chrono::Utc::now(),
-        open: response.open,
-        clicks: response.clicks,
-    })
-}
+        let updated_mail_response: UpdateMailResponse = response.into();
 
-/// a function to delete mail from the db relation...
-pub async fn delete_mail(mail_id: String) -> Result<DeleteMailResponse, AppError> {
-    let mail_repository = Arc::new(MailRepositoryImpl);
-    let mail_service = MailService::new(mail_repository);
+        Ok(updated_mail_response)
+    }
 
-    let response = mail_service.delete_mail(mail_id).await?;
+    async fn get_mails_by_contact(&self, contact_id: Uuid) -> Result<Vec<MailWithDetails>, AppError> {
+        let response = self.repository.get_mails_by_contact(contact_id).await?;
 
-    Ok(DeleteMailResponse {
-        id: response.id,
-        status: Some(response.status),
-        contact_id: Some(response.contact_id),
-    })
-}
+        Ok(response)
+    }
 
-pub async fn increment_mail_clicks(mail_id: String) -> Result<UpdateMailResponse, AppError> {
-    let mail_repository = Arc::new(MailRepositoryImpl);
-    let mail_service = MailService::new(mail_repository);
-
-    let response = mail_service.increment_mail_clicks(mail_id).await?;
-
-    Ok(UpdateMailResponse {
-        id: response.id,
-        mail_message: response.mail_message,
-        template_id: response.template_id,
-        campaign_id: response.campaign_id,
-        status: Some(response.status),
-        updated_at: chrono::Utc::now(),
-        open: response.open,
-        clicks: response.clicks,
-    })
-}
+    async fn fetch_queued_mails(&self) -> Result<Vec<MailWithDetails>, AppError> {
+        let response = self.repository.get_queued_mails().await?;
 
-pub async fn get_mails_by_contact(contact_id: Uuid) -> Result<Vec<MailWithDetails>, AppError> {
-    let mail_repository = Arc::new(MailRepositoryImpl);
-    let mail_service = MailService::new(mail_repository);
+        Ok(response)
+    }
 
-    let response = mail_service.get_mails_by_contact(contact_id).await?;
+    /// Process queued mails with per-server rate limiting using the governor crate...
+    async fn process_mails(
+        &self,
+        server_service: Arc<ServerService>,
+    ) -> Result<(), AppError> {
+        // Create a rate limiter for each server...
+        let mut limiters: HashMap<Uuid, ServerState> = HashMap::new();
+        for server in server_service.get_all_servers().await? {
+            // rate_limit defines max tokens per second
+            let per_sec = NonZeroU32::new(server.rate_limit as u32)
+                .unwrap_or_else(|| NonZeroU32::new(1).unwrap());
+            let quota = Quota::per_second(per_sec);
+
+            let limiter = RateLimiter::direct(quota);
+
+            let server_state = ServerState {
+                limiter,
+                server_type: server.server_type,
+            };
+
+            limiters.insert(server.id, server_state);
+        }
+
+        // run the process in a loop each second...
+        let mut ticker = interval(Duration::from_secs(5));
+        loop {
+            ticker.tick().await;
+
+
+            let mails = self.fetch_queued_mails().await?;
+
+            if mails.is_empty() {
+                println!("No queued mails to process");
+                continue;
+            }
+            for mail in mails {
+                let sid = match mail.server_id {
+                    Some(id) => id,
+                    None => continue,
+                };
+
+                if let Some(server_state) = limiters.get(&sid) {
+                    println!("[Server {:?}] waiting for token to send mail {} to {}", sid, mail.id, mail.email);
+                    let start = Instant::now();
+                    // try by adding the until_ready() to the limiter...
+                    server_state.limiter.until_ready().await;
+                    let waited = start.elapsed();
+                    println!("[Server {:?}] waited {:?} before sending mail {}", sid, waited, mail.id);
+                    let email = mail.email.clone();
+
+                    // create n background task to send the email bound by server rate limit...
+                    tokio::spawn(
+                        send_single_email(
+                            server_state.server_type,
+                            mail.id.clone(),
+                            mail.campaign_id.unwrap(),
+                            sid,
+                            email,
+                            mail.mail_message.clone(),
+                            format!("Hello {}", mail.email),
+                        )
+                    );
+
+                    // Update status on success
+                    self.repository.update_mail_status(mail.id, "submitted").await?;
+                }
+            }
+        }
+    }
+}
 
-    Ok(response)
+/// Process exactly one batch of queued mails (no loop or ticker).
+/// the function for testing...
+pub async fn process_one_batch(
+    servers: &HashMap<Uuid, ServerState>,   // server details...
+    fetch: impl Fn() -> Vec<MailWithDetails> + Send + Sync, // fetch all the mailDetails...
+    send: impl Fn(&MailWithDetails) + Send + Sync,  // send the emails...
+    update: impl Fn(String) + Send + Sync,  // update the mail status...
+) {
+    for mail in fetch() {
+        if let Some(state) = servers.get(&mail.server_id.unwrap()) {
+            state.limiter.until_ready().await;
+            send(&mail);
+            update(mail.id.clone());
+        }
+    }
 }
\ No newline at end of file
diff --git a/backend/src/services/template_service.rs b/backend/src/services/template_service.rs
index 866f83f..d1575e0 100644
--- a/backend/src/services/template_service.rs
+++ b/backend/src/services/template_service.rs
@@ -161,6 +161,7 @@ pub async fn send_templated_email(
         Some(bcc_list.clone()),
         &payload.subject,
         &parsed_html,
+        None,
     )
     .await?;
 
diff --git a/backend/src/utils/bounce_logs.rs b/backend/src/utils/bounce_logs.rs
new file mode 100644
index 0000000..5188552
--- /dev/null
+++ b/backend/src/utils/bounce_logs.rs
@@ -0,0 +1,9 @@
+use crate::models::bounce_logs::Message;
+
+pub fn search_header_from_header_list(message: &Message, header_name:&str) -> Option<String> {
+    let message_id = message.mail.headers.iter()
+    .find(|header| header.name.eq_ignore_ascii_case(header_name))
+    .map(|header| header.value.clone());
+
+    message_id
+}
\ No newline at end of file
diff --git a/backend/tests/rate_limiting.rs b/backend/tests/rate_limiting.rs
new file mode 100644
index 0000000..e107aaf
--- /dev/null
+++ b/backend/tests/rate_limiting.rs
@@ -0,0 +1,126 @@
+use std::{sync::{Arc, Mutex}, time::Duration, collections::HashMap};
+use tokio::time::Instant;
+use uuid::Uuid;
+use chrono::Utc;
+
+use backend::{models::mail::{Mail, MailWithDetails}, services::mail_service::MailServiceTrait};
+use backend::repositories::mail_repository::MockMailRepository;
+use backend::servers::{
+    servers_model::{Server, ServerTypeEnum, TlsTypeEnum},
+    servers_repo::MockServerRepo,
+    servers_services::ServerService,
+};
+use backend::services::mail_service::MailService;
+
+
+#[tokio::test]
+async fn test_process_mails_rate_limiting() {
+    // mock server with rate_limit of 1 mail/sec
+    let server_id = Uuid::new_v4();
+    let fake_server = Server {
+        id: server_id,
+        active: true,
+        host: "smtp.test".into(),
+        smtp_username: "user1".into(),
+        smtp_password: "pass".into(),
+        namespace_id: Uuid::new_v4(),
+        tls_type: TlsTypeEnum::SSLTLS,
+        port: 587,
+        server_type: ServerTypeEnum::SMTP,
+        aws_credentials: None,
+        created_at: Utc::now(),
+        updated_at: Utc::now(),
+        default_from_email: "noreply@test".into(),
+        rate_limit: 1,
+    };
+    let mut mock_srv_repo = MockServerRepo::new();
+    mock_srv_repo
+        .expect_get_all_servers()
+        .returning(move || Ok(vec![fake_server.clone()]));
+    let server_service = Arc::new(ServerService::new(Arc::new(mock_srv_repo)));
+
+    // mock mail repo that returns exactly one queued mail each tick...
+    let mail_id = "m1".to_string();
+    let mut mock_mail_repo = MockMailRepository::new();
+    // every call to get_queued_mails returns our single pending mail...
+    mock_mail_repo
+        .expect_get_queued_mails()
+        .returning(move || {
+            Ok(vec![ MailWithDetails {
+                id: mail_id.clone(),
+                mail_message: "hi".into(),
+                template_id: None,
+                campaign_id: Some(Uuid::new_v4()),
+                server_id: Some(server_id),
+                sent_at: Utc::now(),
+                status: "pending".into(),
+                open: None,
+                clicks: 0,
+                scheduled_at: Utc::now(),
+                attempts: 0,
+                last_error: None,
+                email: "abc@example.com".into(),
+                reason: None,
+            }])
+        });
+
+    // record the instants when update_mail_status is called...
+    let times = Arc::new(Mutex::new(Vec::new()));
+    let times_clone = times.clone();
+    mock_mail_repo
+        .expect_update_mail_status()
+        .returning(move |id, new_status| {
+            // record the instant...
+            times_clone.lock().unwrap().push(Instant::now());
+            // return some dummy Mail back to caller...
+            Ok(Mail {
+                id: id.clone(),
+                mail_message: "".into(),
+                contact_id: Uuid::new_v4(),
+                template_id: None,
+                campaign_id: None,
+                sent_at: Utc::now(),
+                status: new_status.to_string(),
+                open: None,
+                clicks: 0,
+                server_id: None,
+                scheduled_at: Utc::now(),
+                attempts: 0,
+                last_error: None,
+            })
+        });
+
+    let mail_service = Arc::new(MailService::new(Arc::new(mock_mail_repo)));
+
+    // run the real worker (process) in the background...
+    let handle = tokio::spawn({
+        let mail_service = mail_service.clone();
+        let server_service = server_service.clone();
+        async move {
+            mail_service.process_mails(server_service).await.unwrap();
+        }
+    });
+    tokio::time::sleep(Duration::from_secs(10)).await;
+    handle.abort();
+
+    // assert we got at least two updates, each ≥1s apart...
+    let sent = times.lock().unwrap();
+    assert!(
+        sent.len() >= 2, 
+        "sent.len()={}", 
+        sent.len()
+    );
+    assert!(
+        sent.len() <= 10,
+        "Expected at most 10 mails sent, but got {}",
+        sent.len()
+    );
+    for window in sent.windows(2) {
+        let delta = window[1] - window[0];
+        assert!(
+            delta >= Duration::from_secs(1),
+            "two sends too close: {:?}",
+            delta
+        );
+    }
+}
diff --git a/backend/tests/servers.rs b/backend/tests/servers.rs
index 6f2e199..32b9782 100644
--- a/backend/tests/servers.rs
+++ b/backend/tests/servers.rs
@@ -1,7 +1,6 @@
 use std::sync::Arc;
 use axum::http::StatusCode;
 use backend::error::AppError;
-use backend::schema::sql_types::ServerType;
 use backend::servers::servers_model::{Server, ServerRequest, TlsTypeEnum, ServerTypeEnum};
 use backend::servers::servers_repo::MockServerRepo;
 use backend::servers::servers_services::{ServerService, ServerServiceTrait};
@@ -23,6 +22,7 @@ async fn test_create_server() {
         aws_credentials: None,
         port: 587,
         default_from_email: "user@example.com".to_string(),
+        rate_limit: 30,
     };
     let expected_server = Server {
         id: Uuid::new_v4(),
@@ -38,6 +38,7 @@ async fn test_create_server() {
         created_at: Utc::now(),
         updated_at: Utc::now(),
         default_from_email: "user@example.com".to_string(),
+        rate_limit: 30,
     };
     mock_repo
         .expect_create_server()
@@ -69,6 +70,7 @@ async fn test_get_all_servers() {
             created_at: Utc::now(),
             updated_at: Utc::now(),
             default_from_email: "user@example.com".to_string(),
+            rate_limit: 30,
         }
     ];
     mock_repo.expect_get_all_servers().returning(move || Ok(expected_servers.clone()));
@@ -99,6 +101,7 @@ async fn test_get_server_by_id() {
         created_at: Utc::now(),
         updated_at: Utc::now(),
         default_from_email: "user@example.com".to_string(),
+        rate_limit: 30,
     };
     mock_repo.expect_get_server_by_id().with(eq(server_id)).returning(move |_| Ok(expected_server.clone()));
     let server_service = ServerService::new(Arc::new(mock_repo));
@@ -145,6 +148,7 @@ async fn test_update_server() {
         aws_credentials: None,
         port: 465,
         default_from_email: "user@example.com".to_string(),
+        rate_limit: 30,
     };
     let updated_server = Server {
         id: server_id,
@@ -160,6 +164,7 @@ async fn test_update_server() {
         created_at: Utc::now(),
         updated_at: Utc::now(),
         default_from_email: "user@example.com".to_string(),
+        rate_limit: 30,
     };
     mock_repo.expect_update_server().with(eq(server_id), eq(update_payload.clone())).returning(move |_, _| Ok(updated_server.clone()));
     let server_service = ServerService::new(Arc::new(mock_repo));
@@ -186,6 +191,7 @@ async fn test_delete_server() {
         created_at: Utc::now(),
         updated_at: Utc::now(),
         default_from_email: "user@example.com".to_string(),
+        rate_limit: 30,
     };
     mock_repo.expect_delete_server().with(eq(server_id)).returning(move |_| Ok(expected_server.clone()));
     let server_service = ServerService::new(Arc::new(mock_repo));
diff --git a/frontend/app/dashboard/campaigns/[id]/analytics/_columns.tsx b/frontend/app/dashboard/campaigns/[id]/analytics/_columns.tsx
index a99b999..7bae8d3 100644
--- a/frontend/app/dashboard/campaigns/[id]/analytics/_columns.tsx
+++ b/frontend/app/dashboard/campaigns/[id]/analytics/_columns.tsx
@@ -9,8 +9,9 @@ import ToolTip from '@/components/common/ToolTip';
 
 const statusTagStyleMap = {
     draft: 'bg-gray-100 text-gray-800',
-    pending: 'bg-yellow-100 text-yellow-800',
-    sent: 'bg-blue-100 text-blue-800',
+    queued: 'bg-yellow-100 text-yellow-800',
+    submitted: 'bg-blue-100 text-blue-800',
+    delivered: 'bg-green-100 text-green-800',
     bounced: 'bg-red-100 text-red-800',
 }
 
diff --git a/frontend/app/dashboard/contacts/[id]/mails/_columns.tsx b/frontend/app/dashboard/contacts/[id]/mails/_columns.tsx
index 4a89923..2a3d51c 100644
--- a/frontend/app/dashboard/contacts/[id]/mails/_columns.tsx
+++ b/frontend/app/dashboard/contacts/[id]/mails/_columns.tsx
@@ -9,8 +9,8 @@ import TemplateName from './components/TemplateName';
 
 const statusTagStyleMap = {
     draft: 'bg-gray-100 text-gray-800',
-    pending: 'bg-yellow-100 text-yellow-800',
-    sent: 'bg-blue-100 text-blue-800',
+    queued: 'bg-yellow-100 text-yellow-800',
+    delivered: 'bg-blue-100 text-blue-800',
     bounced: 'bg-red-100 text-red-800',
 }
 
diff --git a/frontend/app/dashboard/servers/_components/AwsServerForm.tsx b/frontend/app/dashboard/servers/_components/AwsServerForm.tsx
index 15df928..e422601 100644
--- a/frontend/app/dashboard/servers/_components/AwsServerForm.tsx
+++ b/frontend/app/dashboard/servers/_components/AwsServerForm.tsx
@@ -17,6 +17,7 @@ import {
   FieldErrors,
 } from "react-hook-form";
 import { Server } from "@/lib/type";
+import serverRegions from "../_constants/server";
 
 interface AwsServerFormProps {
   register: UseFormRegister<Server>;
@@ -78,40 +79,13 @@ export default function AwsServerForm({
                   <SelectValue placeholder="Select Region" />
                 </SelectTrigger>
                 <SelectContent>
-                  <SelectItem value="us-east-1">
-                    US East (N. Virginia)
-                  </SelectItem>
-                  <SelectItem value="us-east-2">US East (Ohio)</SelectItem>
-                  <SelectItem value="us-west-1">
-                    US West (N. California)
-                  </SelectItem>
-                  <SelectItem value="us-west-2">US West (Oregon)</SelectItem>
-                  <SelectItem value="ap-south-1">
-                    Asia Pacific (Mumbai)
-                  </SelectItem>
-                  <SelectItem value="ap-northeast-2">
-                    Asia Pacific (Seoul)
-                  </SelectItem>
-                  <SelectItem value="ap-southeast-1">
-                    Asia Pacific (Singapore)
-                  </SelectItem>
-                  <SelectItem value="ap-southeast-2">
-                    Asia Pacific (Sydney)
-                  </SelectItem>
-                  <SelectItem value="ap-northeast-1">
-                    Asia Pacific (Tokyo)
-                  </SelectItem>
-                  <SelectItem value="ca-central-1">Canada (Central)</SelectItem>
-                  <SelectItem value="eu-central-1">
-                    Europe (Frankfurt)
-                  </SelectItem>
-                  <SelectItem value="eu-west-1">Europe (Ireland)</SelectItem>
-                  <SelectItem value="eu-west-2">Europe (London)</SelectItem>
-                  <SelectItem value="eu-west-3">Europe (Paris)</SelectItem>
-                  <SelectItem value="eu-north-1">Europe (Stockholm)</SelectItem>
-                  <SelectItem value="sa-east-1">
-                    South America (São Paulo)
-                  </SelectItem>
+                  {
+                    serverRegions.map(region => (
+                      <SelectItem key={region.label} value={region.value}>
+                        { region.label }
+                      </SelectItem>
+                    ))
+                  }
                 </SelectContent>
               </Select>
             )}
@@ -131,20 +105,37 @@ export default function AwsServerForm({
           />
         </div>
       </div>
-
-      <div className="space-y-2">
-        <Label>Default From Email</Label>
+      
+      <div className="grid md:grid-cols-[2fr,1fr] gap-4">
+        <div className="space-y-2">
+          <Label>Default From Email</Label>
+            <Input
+              {...register("default_from_email", {
+                onChange: () => trigger("default_from_email"),
+              })}
+              placeholder="from.email@test.io"
+            />
+            {errors.default_from_email && (
+              <span className="text-sm text-destructive">
+                {errors.default_from_email.message}
+              </span>
+            )}
+        </div>
+        <div className="space-y-2">
+          <Label>Rate Limit</Label>
           <Input
-            {...register("default_from_email", {
-              onChange: () => trigger("default_from_email"),
+            {...register("rate_limit", {
+              onChange: () => trigger("rate_limit"),
+              valueAsNumber: true,
             })}
-            placeholder="from.email@test.io"
+            placeholder="30"
           />
-          {errors.default_from_email && (
+          {errors.rate_limit && (
             <span className="text-sm text-destructive">
-              {errors.default_from_email.message}
+              {errors.rate_limit.message}
             </span>
           )}
+        </div>
       </div>
     </>
   );
diff --git a/frontend/app/dashboard/servers/_components/ServerCard.tsx b/frontend/app/dashboard/servers/_components/ServerCard.tsx
index 2f4aa75..dd699ef 100644
--- a/frontend/app/dashboard/servers/_components/ServerCard.tsx
+++ b/frontend/app/dashboard/servers/_components/ServerCard.tsx
@@ -51,6 +51,7 @@ export default function ServerCard({ server, onCancel }: ServerCardProps) {
   const testAndSaveSmtpConnection = async () => {
     try {
       const formData = getValues();
+      console.log("THE FORM VALUE FROM THE SERVER ===> ", formData);
       const payload = { ...formData };
 
       const result = await checkCredentials(payload).unwrap();
diff --git a/frontend/app/dashboard/servers/_components/SmtpServerForm.tsx b/frontend/app/dashboard/servers/_components/SmtpServerForm.tsx
index 45b0ec4..efd8688 100644
--- a/frontend/app/dashboard/servers/_components/SmtpServerForm.tsx
+++ b/frontend/app/dashboard/servers/_components/SmtpServerForm.tsx
@@ -130,7 +130,21 @@ export default function SmtpServerForm({
         </div>
       </div>
 
-      <div className="grid md:grid-cols-2 gap-4">
+      <div className="grid md:grid-cols-[2fr,1fr,1fr] gap-4">
+        <div className="space-y-2">
+          <Label>Default From Email</Label>
+            <Input
+              {...register("default_from_email", {
+                onChange: () => trigger("default_from_email"),
+              })}
+              placeholder="from.email@test.io"
+            />
+            {errors.default_from_email && (
+              <span className="text-sm text-destructive">
+                {errors.default_from_email.message}
+              </span>
+            )}
+        </div>
         <div className="space-y-2">
           <Label>TLS Configuration</Label>
           <Controller
@@ -156,16 +170,17 @@ export default function SmtpServerForm({
           )}
         </div>
         <div className="space-y-2">
-        <Label>Default From Email</Label>
+          <Label>Rate Limit</Label>
           <Input
-            {...register("default_from_email", {
-              onChange: () => trigger("default_from_email"),
+            {...register("rate_limit", {
+              onChange: () => trigger("rate_limit"),
+              valueAsNumber: true,
             })}
-            placeholder="from.email@test.io"
+            placeholder="30"
           />
-          {errors.default_from_email && (
+          {errors.rate_limit && (
             <span className="text-sm text-destructive">
-              {errors.default_from_email.message}
+              {errors.rate_limit.message}
             </span>
           )}
         </div>
diff --git a/frontend/app/dashboard/servers/_constants/server.ts b/frontend/app/dashboard/servers/_constants/server.ts
new file mode 100644
index 0000000..d510f30
--- /dev/null
+++ b/frontend/app/dashboard/servers/_constants/server.ts
@@ -0,0 +1,68 @@
+const serverRegions = [
+    {
+      label: 'US East (N. Virginia)',
+      value: 'us-east-1',
+    },
+    {
+      label: 'US East (Ohio)',
+      value: 'us-east-2',
+    },
+    {
+      label: 'US West (N. California)',
+      value: 'us-west-1',
+    },
+    {
+      label: 'US West (Oregon)',
+      value: 'us-west-2',
+    },
+    {
+      label: 'Asia Pacific (Mumbai)',
+      value: 'ap-south-1',
+    },
+    {
+      label: 'Asia Pacific (Seoul)',
+      value: 'ap-northeast-2',
+    },
+    {
+      label: 'Asia Pacific (Singapore)',
+      value: 'ap-southeast-1',
+    },
+    {
+      label: 'Asia Pacific (Sydney)',
+      value: 'ap-southeast-2',
+    },
+    {
+      label: 'Asia Pacific (Tokyo)',
+      value: 'ap-northeast-1',
+    },
+    {
+      label: 'Canada (Central)',
+      value: 'ca-central-1',
+    },
+    {
+      label: 'Europe (Frankfurt)',
+      value: 'eu-central-1',
+    },
+    {
+      label: 'Europe (Ireland)',
+      value: 'eu-west-1',
+    },
+    {
+      label: 'Europe (London)',
+      value: 'eu-west-2',
+    },
+    {
+      label: 'Europe (Paris)',
+      value: 'eu-west-3',
+    },
+    {
+      label: 'Europe (Stockholm)',
+      value: 'eu-north-1',
+    },
+    {
+      label: 'South America (São Paulo)',
+      value: 'sa-east-1',
+    },
+];
+
+export default serverRegions;
\ No newline at end of file
diff --git a/frontend/app/layout.tsx b/frontend/app/layout.tsx
index 084f6f1..e5f3d4a 100644
--- a/frontend/app/layout.tsx
+++ b/frontend/app/layout.tsx
@@ -14,8 +14,8 @@ const geistMono = Geist_Mono({
 });
 
 export const metadata: Metadata = {
-  title: "Create Next App",
-  description: "Generated by create next app",
+  title: "Mail Service",
+  description: "An email management platform",
 };
 
 export default function RootLayout({
diff --git a/frontend/app/services/CampaignApi.ts b/frontend/app/services/CampaignApi.ts
index d6053e3..46681ba 100644
--- a/frontend/app/services/CampaignApi.ts
+++ b/frontend/app/services/CampaignApi.ts
@@ -25,10 +25,7 @@ export const campaignApi = createApi({
     // Query to fetch all lists...
     getCampaigns: builder.query<Campaign[], void>({
       query: () => "",
-      providesTags: (result) =>
-        result
-          ? result.map((campaign) => ({ type: "Campaign", id: campaign.id }))
-          : [{ type: "Campaign" }],
+      providesTags: ["Campaign"],
     }),
     getCampaignById: builder.query<Campaign, string>({
       query: (campaignId) => `/${campaignId}`,
@@ -42,7 +39,7 @@ export const campaignApi = createApi({
         method: "POST",
         body: newCampaign,
       }),
-      invalidatesTags: [{ type: "Campaign" }],
+      invalidatesTags: ["Campaign"],
     }),
     updateCampaign: builder.mutation<
       UpdateCampaignResponse,
@@ -62,7 +59,7 @@ export const campaignApi = createApi({
           console.error("Error updating campaign:", err);
         }
       },
-      invalidatesTags: [{ type: "Campaign" }],
+      invalidatesTags: ["Campaign"],
     }),
     deleteCampaign: builder.mutation<void, string>({
       query: (campaignId) => ({
@@ -80,7 +77,7 @@ export const campaignApi = createApi({
         method: "POST",
         body: { list_id: listId },
       }),
-      invalidatesTags: [{ type: "Campaign" }],
+      invalidatesTags: ["Campaign"],
     }),
   }),
 });
diff --git a/frontend/components/Sidebar.tsx b/frontend/components/Sidebar.tsx
index f089332..46ed164 100644
--- a/frontend/components/Sidebar.tsx
+++ b/frontend/components/Sidebar.tsx
@@ -74,15 +74,15 @@ const Sidebar = ({ onClose }: SidebarProps) => {
         </button>
       )}
 
-      <nav className="flex flex-col space-y-1 p-4 pt-16 md:pt-4">
+      <nav className="flex flex-col space-y-1 py-16 md:pt-4">
         {sidebarItems.map((item, index) => (
-          <div key={index}>
+          <div key={index} className="pl-2">
             {item.subItems ? (
               <div className="flex flex-col">
                 <button
                   onClick={() => toggleExpand(item.name)}
                   className={cn(
-                    "flex items-center justify-between px-4 py-2 rounded-md text-gray-700 hover:bg-gray-100 hover:text-gray-900 transition w-full",
+                    "flex items-center justify-between px-4 py-2 text-gray-700 hover:bg-gray-100 hover:text-gray-900 transition w-full",
                     normalizedPathname.startsWith(item.href)
                       ? "text-blue-600 font-medium"
                       : ""
@@ -100,7 +100,7 @@ const Sidebar = ({ onClose }: SidebarProps) => {
                         key={subIndex}
                         href={subItem.href}
                         className={cn(
-                          "flex items-center space-x-3 px-4 py-2 rounded-md text-gray-700 hover:bg-gray-100 hover:text-gray-900 transition",
+                          "flex items-center space-x-3 px-4 py-2 text-gray-700 hover:bg-gray-100 hover:text-gray-900 transition ml-2",
                           normalizedPathname === subItem.href
                             ? "text-blue-600 font-medium border-r-4 border-blue-600"
                             : ""
@@ -117,7 +117,7 @@ const Sidebar = ({ onClose }: SidebarProps) => {
               <Link
                 href={item.href}
                 className={cn(
-                  "flex items-center space-x-3 px-4 py-2 rounded-md text-gray-700 hover:bg-gray-100 hover:text-gray-900 transition",
+                  "flex items-center space-x-3 px-4 py-2 text-gray-700 hover:bg-gray-100 hover:text-gray-900 transition",
                   normalizedPathname === item.href
                     ? "text-blue-600 font-medium border-r-4 border-blue-600"
                     : ""
diff --git a/frontend/hooks/useServerForm.ts b/frontend/hooks/useServerForm.ts
index 69bf2df..67fa10a 100644
--- a/frontend/hooks/useServerForm.ts
+++ b/frontend/hooks/useServerForm.ts
@@ -41,6 +41,8 @@ export function useServerForm(server: Partial<Server>) {
         region: "ap-southeast-1",
         session_token: null,
       },
+      default_from_email: server.default_from_email ?? "",
+      rate_limit: server.rate_limit ?? 30,
     },
     mode: "all",
     reValidateMode: "onChange",
@@ -86,6 +88,8 @@ export function useServerForm(server: Partial<Server>) {
           region: server.aws_credentials?.region || "ap-southeast-1",
           session_token: server.aws_credentials?.session_token || null,
         },
+        default_from_email: server.default_from_email ?? "",
+        rate_limit: server.rate_limit ?? 30,
       });
     }
   }, [server, reset]);
@@ -112,6 +116,8 @@ export function useServerForm(server: Partial<Server>) {
             region: data.aws_credentials?.region || "ap-southeast-1",
             session_token: data.aws_credentials?.session_token || null,
           },
+          default_from_email: server.default_from_email ?? "",
+          rate_limit: server.rate_limit ?? 30,
         };
       } else {
         // If SMTP, set default values for AWS fields
diff --git a/frontend/lib/type.ts b/frontend/lib/type.ts
index ad0611e..bd4283f 100644
--- a/frontend/lib/type.ts
+++ b/frontend/lib/type.ts
@@ -76,6 +76,7 @@ export const ServerSchema = z.object({
   }),
   created_at: z.string().optional(),
   updated_at: z.string().optional(),
+  rate_limit: z.number().int().min(1).max(1000).default(60),
 });
 
 export type Server = z.infer<typeof ServerSchema>;
diff --git a/frontend/lib/type/server.ts b/frontend/lib/type/server.ts
index 47f16f1..59a848c 100644
--- a/frontend/lib/type/server.ts
+++ b/frontend/lib/type/server.ts
@@ -14,4 +14,6 @@ export interface Server {
   smtp_username?: string;
   smtp_password?: string;
   aws_credentials?: AwsCredentials;
+  default_email?: string;
+  rate_limit?: number;
 }