diff --git a/.github/workflows/release.yml b/.github/workflows/release.yml
index 9c719670..46c01a10 100644
--- a/.github/workflows/release.yml
+++ b/.github/workflows/release.yml
@@ -70,9 +70,25 @@ jobs:
           NODE_AUTH_TOKEN: ${{ secrets.NPM_TOKEN }}
 
       - run: rm -rf node_modules/.cache/rollup-plugin-typescript2
+      - name: Determine version specifier from commit title
+        id: specifier
+        env:
+          COMMIT_MSG: ${{ github.event.head_commit.message }}
+        run: |
+          TITLE=$(printf '%s' "$COMMIT_MSG" | head -n1)
+          echo "Commit title: $TITLE"
+          if printf '%s' "$TITLE" | grep -qE '^feat(\(.+\))?!?:'; then
+            SPECIFIER=minor
+          elif printf '%s' "$TITLE" | grep -qE '^fix(\(.+\))?!?:'; then
+            SPECIFIER=patch
+          else
+            SPECIFIER=patch
+          fi
+          echo "Resolved specifier: $SPECIFIER"
+          echo "specifier=$SPECIFIER" >> "$GITHUB_OUTPUT"
       - name: Release
         run: |
-          npx nx release --specifier=patch --yes
+          npx nx release --specifier=${{ steps.specifier.outputs.specifier }} --yes
         env:
           GITHUB_TOKEN: ${{ secrets.GH_TOKEN }}
           NODE_AUTH_TOKEN: ${{ secrets.NPM_TOKEN }}
diff --git a/.gitignore b/.gitignore
index e5c49852..da64f306 100644
--- a/.gitignore
+++ b/.gitignore
@@ -26,6 +26,9 @@ node_modules
 !.vscode/extensions.json
 .cursor
 
+/.env
+/.env.local
+
 # misc
 /.sass-cache
 /connect.lock
diff --git a/docs/guide/wallet-providers/para.md b/docs/guide/wallet-providers/para.md
index f7a4f66c..f5e65160 100644
--- a/docs/guide/wallet-providers/para.md
+++ b/docs/guide/wallet-providers/para.md
@@ -8,19 +8,19 @@ Run the following command to install the necessary packages:
 
 {% tabs %}
 {% tab title="npm" %}
-<pre class="language-bash"><code class="lang-bash"><strong>npm install @justweb3/widget @getpara/react-sdk @getpara/wagmi-v2-integration wagmi @tanstack/react-query ethers
+<pre class="language-bash"><code class="lang-bash"><strong>npm install @justweb3/widget @getpara/react-sdk @getpara/wagmi-v2-integration wagmi @tanstack/react-query
 </strong></code></pre>
 {% endtab %}
 
 {% tab title="pnpm" %}
 ```bash
-pnpm install @justweb3/widget @getpara/react-sdk @getpara/wagmi-v2-integration wagmi @tanstack/react-query ethers
+pnpm install @justweb3/widget @getpara/react-sdk @getpara/wagmi-v2-integration wagmi @tanstack/react-query
 ```
 {% endtab %}
 
 {% tab title="yarn" %}
 ```bash
-yarn add @justweb3/widget @getpara/react-sdk @getpara/wagmi-v2-integration wagmi @tanstack/react-query ethers
+yarn add @justweb3/widget @getpara/react-sdk @getpara/wagmi-v2-integration wagmi @tanstack/react-query
 ```
 {% endtab %}
 {% endtabs %}
diff --git a/docs/sdk/JustaName Core SDK/README.md b/docs/sdk/JustaName Core SDK/README.md
index fc98e0d4..4fb8e676 100644
--- a/docs/sdk/JustaName Core SDK/README.md	
+++ b/docs/sdk/JustaName Core SDK/README.md	
@@ -60,7 +60,7 @@ First, import the JustaName SDK and initialize it with your configuration:
 
 ```typescript
 import { JustaName } from '@justaname.id/sdk';
-import { ethers } from 'ethers';
+import { privateKeyToAccount, generatePrivateKey } from 'viem/accounts';
 
 // Initialize the SDK with your configuration
 const justaname = JustaName.init({
@@ -85,7 +85,7 @@ const justaname = JustaName.init({
 });
 
 // Create a signer (for example purposes, we're creating a random wallet)
-const signer = ethers.Wallet.createRandom();
+const signer = privateKeyToAccount(generatePrivateKey());
 ```
 
 ### Issuing a Subname
@@ -98,7 +98,7 @@ async function issueSubname() {
         chainId: 1 // Ethereum Mainnet
     });
     
-    const signature = await signer.signMessage(challenge.challenge);
+    const signature = await signer.signMessage({ message: challenge.challenge });
     
     const response = await justaname.subnames.addSubname(
     {
@@ -125,7 +125,7 @@ async function updateSubname() {
         chainId: 1
     });
     
-    const signature = await signer.signMessage(challenge.challenge);
+    const signature = await signer.signMessage({ message: challenge.challenge });
     
     const response = await justaname.subnames.updateSubname(
     {
@@ -159,7 +159,7 @@ async function signIn() {
         address: signer.address
     });
     
-    const signature = await signer.signMessage(message);
+    const signature = await signer.signMessage({ message });
     
     const response = await justaname.signIn.signIn({
         message: message,
diff --git a/docs/sdk/siwens/README.md b/docs/sdk/siwens/README.md
index e912f1a9..de9e47b9 100644
--- a/docs/sdk/siwens/README.md
+++ b/docs/sdk/siwens/README.md
@@ -48,12 +48,12 @@ yarn add @justaname.id/siwens
 ### Example Usage
 ```typescript
 import { SIWENS, InvalidDomainException, InvalidENSException, InvalidStatementException, InvalidTimeException } f, InvalidDomainException, InvalidENSException, InvalidStatementException, InvalidTimeException } from '@justaname.id/siwens';rom '@justaname.id/siwens';
-import { ethers } from 'ethers';
+import { privateKeyToAccount } from 'viem/accounts';
 
 // Define your provider URL (e.g., Infura)
 const providerUrl = 'https://mainnet.infura.io/v3/YOUR_INFURA_KEY';
 
-const signer = new ethers.Wallet('YOUR_PRIVATE_KEY_ENS_HOLDER')
+const signer = privateKeyToAccount('YOUR_PRIVATE_KEY_ENS_HOLDER')
 
 async function signInUser() {
    const siwens = new SIWENS({
@@ -66,7 +66,7 @@ async function signInUser() {
       providerUrl
     });
    const message = await siwens.prepareMessage();
-   const signature = await signer.signMessage(message);
+   const signature = await signer.signMessage({ message });
    return signature;
 }
 
diff --git a/package.json b/package.json
index d488bb73..1a7840c7 100644
--- a/package.json
+++ b/package.json
@@ -77,7 +77,6 @@
     "react-router-dom": "6.11.2",
     "react-timer-hook": "3.0.8",
     "react-tiny-popover": "8.0.4",
-    "siwe": "2.3.2",
     "tailwind-merge": "2.5.2",
     "tailwindcss-animate": "1.0.7",
     "tslib": "2.3.0",
diff --git a/packages/@justaname.id/sdk/README.md b/packages/@justaname.id/sdk/README.md
index 136f2e2d..3759edef 100644
--- a/packages/@justaname.id/sdk/README.md
+++ b/packages/@justaname.id/sdk/README.md
@@ -56,7 +56,7 @@ First, import the JustaName SDK and initialize it with your configuration:
 
 ```typescript
 import { JustaName } from '@justaname.id/sdk';
-import { ethers } from 'ethers';
+import { privateKeyToAccount, generatePrivateKey } from 'viem/accounts';
 
 // Initialize the SDK with your configuration
 const justaname = JustaName.init({
@@ -80,8 +80,8 @@ const justaname = JustaName.init({
     }
 });
 
-// Create a signer (for example purposes, we're creating a random wallet)
-const signer = ethers.Wallet.createRandom();
+// Create a signer (for example purposes, we're creating a random account)
+const signer = privateKeyToAccount(generatePrivateKey());
 ```
 
 ### Issuing a Subname
@@ -94,7 +94,7 @@ async function issueSubname() {
         chainId: 1 // Ethereum Mainnet
     });
     
-    const signature = await signer.signMessage(challenge.challenge);
+    const signature = await signer.signMessage({ message: challenge.challenge });
     
     const response = await justaname.subnames.addSubname(
     {
@@ -121,7 +121,7 @@ async function updateSubname() {
         chainId: 1
     });
     
-    const signature = await signer.signMessage(challenge.challenge);
+    const signature = await signer.signMessage({ message: challenge.challenge });
     
     const response = await justaname.subnames.updateSubname(
     {
@@ -155,7 +155,7 @@ async function signIn() {
         address: signer.address
     });
     
-    const signature = await signer.signMessage(message);
+    const signature = await signer.signMessage({ message });
     
     const response = await justaname.signIn.signIn({
         message: message,
diff --git a/packages/@justaname.id/sdk/package.json b/packages/@justaname.id/sdk/package.json
index 721d209b..6a08ede3 100644
--- a/packages/@justaname.id/sdk/package.json
+++ b/packages/@justaname.id/sdk/package.json
@@ -10,7 +10,6 @@
     "jest": "^29.4.1"
   },
   "peerDependencies": {
-    "siwe": ">=2.0.0",
     "viem": "^2.48.0"
   },
   "exports": {
diff --git a/packages/@justaname.id/sdk/src/lib/features/sign-in/index.ts b/packages/@justaname.id/sdk/src/lib/features/sign-in/index.ts
index c7619201..7f7ce548 100644
--- a/packages/@justaname.id/sdk/src/lib/features/sign-in/index.ts
+++ b/packages/@justaname.id/sdk/src/lib/features/sign-in/index.ts
@@ -8,8 +8,6 @@ import {
 } from '../../errors';
 import { OffchainResolvers } from '../offchain-resolvers';
 import { RequestSignInParams, SignInFunctionParams } from '../../types/signin';
-import { createPublicClient, http } from 'viem';
-import { mainnet, sepolia } from 'viem/chains';
 import { normalize } from 'viem/ens';
 
 export interface SignInResponse extends SiwensResponse {
@@ -110,62 +108,13 @@ export class SignIn {
       providerUrl: network.providerUrl,
     });
 
-    const siwensResponse = await siwens.verify(
-      {
-        signature: params.signature,
-        nonce: params.nonce,
-        domain: params.domain,
-      },
-      {
-        // Smart-contract (EIP-1271) verification is handled inside
-        // `verificationFallback` below using viem's `verifySiweMessage`.
-        // We no longer pass `provider` here because it must be an ethers
-        // `Provider`, and the SDK is now viem-only.
-        verificationFallback: async (params, opts, message, EIP1271Promise) => {
-          // Use the chainId extracted from the SIWE message itself, not the
-          // SDK-default. Otherwise contract-wallet (EIP-1271) verification
-          // runs against the wrong chain when the message is cross-chain.
-          const publicClient = createPublicClient({
-            chain: chainId === 1 ? mainnet : sepolia,
-            transport: http(network.providerUrl),
-          });
-
-          const result = await EIP1271Promise;
-
-          if (result.success) {
-            return result;
-          } else {
-            let signature = params.signature;
-            const lastByte = parseInt(params.signature.slice(-2), 16);
-            if (lastByte < 27) {
-              const adjustedV = (27 + (lastByte % 2))
-                .toString(16)
-                .padStart(2, '0');
-              signature = signature.slice(0, -2) + adjustedV;
-            }
-
-            const viemResponse = await publicClient.verifySiweMessage({
-              message: message.toMessage(),
-              signature: signature as `0x${string}`,
-              address: result.data.address as `0x${string}`,
-              nonce: params.nonce,
-              domain: params.domain as string,
-              time: params.time ? new Date(params.time) : undefined,
-              scheme: params.scheme as string,
-            });
-
-            if (viemResponse) {
-              return {
-                data: result.data,
-                success: true,
-              };
-            }
-
-            return result;
-          }
-        },
-      }
-    );
+    // SIWENS.verify performs EOA recovery, EIP-1271 and ERC-6492 verification
+    // internally via viem (`verifySiweMessage`) against the message's chain.
+    const siwensResponse = await siwens.verify({
+      signature: params.signature,
+      nonce: params.nonce,
+      domain: params.domain,
+    });
 
     if (siwensResponse.data.chainId !== chainId) {
       throw InvalidSignInException.chainIdMismatch(
diff --git a/packages/@justaname.id/sdk/src/lib/features/subname-challenge/index.ts b/packages/@justaname.id/sdk/src/lib/features/subname-challenge/index.ts
index 5d065d22..e8fea9e5 100644
--- a/packages/@justaname.id/sdk/src/lib/features/subname-challenge/index.ts
+++ b/packages/@justaname.id/sdk/src/lib/features/subname-challenge/index.ts
@@ -6,7 +6,9 @@ import {
 } from '../../types';
 import { SiweConfig } from '../../types/siwe/siwe-config';
 import { ChallengeRequestException } from '../../errors/ChallengeRequest.expection';
-import { SiweMessage } from 'siwe';
+import { generateNonce } from '@justaname.id/siwens';
+import { getAddress } from 'viem';
+import { createSiweMessage } from 'viem/siwe';
 
 /**
  * Represents the Sign-In with Ethereum (SIWE) functionality, providing methods
@@ -104,19 +106,18 @@ export class SubnameChallenge {
     const { expirationTime, issuedAt } =
       this.generateIssuedAndExpirationTime(_ttl);
 
-    const siweMessage = new SiweMessage({
+    const prepared = createSiweMessage({
       domain: _domain,
       uri: _origin,
-      address: _address,
+      address: getAddress(_address),
       statement: statement,
       chainId: _chainId,
       version: '1',
-      issuedAt,
-      expirationTime,
+      nonce: generateNonce(),
+      issuedAt: new Date(issuedAt),
+      expirationTime: new Date(expirationTime),
     });
 
-    const prepared = siweMessage.prepareMessage();
-
     if (this.dev) {
       // eslint-disable-next-line no-console
       console.debug(
diff --git a/packages/@justaname.id/siwens/README.md b/packages/@justaname.id/siwens/README.md
index 727d6e1b..3fc11f3c 100644
--- a/packages/@justaname.id/siwens/README.md
+++ b/packages/@justaname.id/siwens/README.md
@@ -44,14 +44,13 @@ yarn add @justaname.id/siwens
 ### Example Usage
 ```typescript
 import { SIWENS, InvalidENSException } from '@justaname.id/siwens';
-import { Wallet } from 'ethers';
+import { privateKeyToAccount } from 'viem/accounts';
 
 // Define your provider URL (e.g., Infura)
 const infuraProjectId = 'YOUR_INFURA_PROJECT_ID';
 const providerUrl = 'https://mainnet.infura.io/v3/' + infuraProjectId;
 
-// const signer = Wallet.createRandom();
-const signer = new Wallet('YOUR_PRIVATE_KEY');
+const signer = privateKeyToAccount('YOUR_PRIVATE_KEY');
 
 async function signInUser() {
    const siwens = new SIWENS({
@@ -67,7 +66,7 @@ async function signInUser() {
       providerUrl
    });
    const message = await siwens.prepareMessage();
-   const signature = await signer.signMessage(message);
+   const signature = await signer.signMessage({ message });
    return {signature, message};
 }
 
diff --git a/packages/@justaname.id/siwens/package.json b/packages/@justaname.id/siwens/package.json
index 1125c483..9cbd9d91 100644
--- a/packages/@justaname.id/siwens/package.json
+++ b/packages/@justaname.id/siwens/package.json
@@ -2,10 +2,10 @@
   "name": "@justaname.id/siwens",
   "version": "0.0.145",
   "dependencies": {
+    "@stablelib/random": "^1.0.2",
     "punycode": "^2.3.1"
   },
   "peerDependencies": {
-    "siwe": ">=2.0.0",
     "viem": "^2.48.0"
   },
   "exports": {
diff --git a/packages/@justaname.id/siwens/src/lib/index.ts b/packages/@justaname.id/siwens/src/lib/index.ts
index 10ca5f1f..652b428b 100644
--- a/packages/@justaname.id/siwens/src/lib/index.ts
+++ b/packages/@justaname.id/siwens/src/lib/index.ts
@@ -1,3 +1,4 @@
 export * from './errors';
+export * from './types';
 export * from './siwens/siwens';
 export * from './utils';
\ No newline at end of file
diff --git a/packages/@justaname.id/siwens/src/lib/siwens/siwens.ts b/packages/@justaname.id/siwens/src/lib/siwens/siwens.ts
index 735df385..e97ec5d3 100644
--- a/packages/@justaname.id/siwens/src/lib/siwens/siwens.ts
+++ b/packages/@justaname.id/siwens/src/lib/siwens/siwens.ts
@@ -1,10 +1,3 @@
-import {
-  generateNonce,
-  SiweMessage,
-  SiweResponse,
-  VerifyOpts,
-  VerifyParams,
-} from 'siwe';
 import {
   InvalidConfigurationException,
   InvalidENSException,
@@ -16,7 +9,16 @@ import {
   checkTTL,
   constructSignInStatement,
   extractDataFromStatement,
+  generateNonce,
 } from '../utils';
+import {
+  SiweError,
+  SiweErrorType,
+  SiweMessageFields,
+  SiweResponse,
+  VerifyOpts,
+  VerifyParams,
+} from '../types';
 import { toASCII, toUnicode } from 'punycode';
 import {
   createPublicClient,
@@ -28,6 +30,11 @@ import {
 import { mainnet, sepolia } from 'viem/chains';
 import type { Chain } from 'viem';
 import { normalize } from 'viem/ens';
+import {
+  createSiweMessage,
+  parseSiweMessage,
+  verifySiweMessage,
+} from 'viem/siwe';
 
 const SUPPORTED_CHAINS: Record<number, Chain> = {
   1: mainnet,
@@ -43,14 +50,18 @@ const buildPublicClient = (
     transport: http(providerUrl),
   });
 
+const toISOStringOrUndefined = (value?: string | Date): string | undefined => {
+  if (!value) {
+    return undefined;
+  }
+  return value instanceof Date ? value.toISOString() : value;
+};
+
 export interface SiwensResponse extends SiweResponse {
   ens: string;
 }
 
-export interface SiwensParams
-  extends Partial<
-    Omit<SiweMessage, 'toMessage' | 'prepareMessage' | 'verify' | 'validate'>
-  > {
+export interface SiwensParams extends Partial<SiweMessageFields> {
   ens: string;
   ttl?: number;
   expirationTime?: string;
@@ -62,19 +73,57 @@ export interface SiwensConfig {
   providerUrl?: string;
 }
 
-export class SIWENS extends SiweMessage {
+/**
+ * Sign-In with ENS message. Previously this extended `siwe`'s `SiweMessage`;
+ * it is now a standalone, ethers-free implementation backed by viem's native
+ * SIWE module (`viem/siwe`). The public surface (fields, `prepareMessage`,
+ * `verify`, `generateNonce`) is preserved.
+ */
+export class SIWENS {
+  readonly scheme?: string;
+  readonly domain: string;
+  readonly address: string;
+  readonly statement?: string;
+  readonly uri: string;
+  readonly version: string;
+  readonly chainId: number;
+  readonly nonce: string;
+  readonly issuedAt?: string;
+  readonly expirationTime?: string;
+  readonly notBefore?: string;
+  readonly requestId?: string;
+  readonly resources?: string[];
   readonly provider: PublicClient;
   readonly providerUrl: string | undefined;
+  /** The raw EIP-4361 message string (parsed input, or the built message). */
+  private readonly message: string;
 
   constructor(signInConfig: SiwensConfig) {
     const { params, providerUrl } = signInConfig;
+
     if (typeof params === 'string') {
-      super(params);
       if (!providerUrl) {
         throw InvalidConfigurationException.providerUrlRequired();
       }
-      this.provider = buildPublicClient(providerUrl, this.chainId);
+      const parsed = parseSiweMessage(params);
+      this.scheme = parsed.scheme;
+      this.domain = parsed.domain as string;
+      // Normalize to EIP-55 checksum so `data.address` matches the casing that
+      // `siwe` always returned (it rejected non-checksummed addresses).
+      this.address = viemGetAddress(parsed.address as string);
+      this.statement = parsed.statement;
+      this.uri = parsed.uri as string;
+      this.version = (parsed.version as string) || '1';
+      this.chainId = (parsed.chainId as number) ?? 1;
+      this.nonce = parsed.nonce as string;
+      this.issuedAt = toISOStringOrUndefined(parsed.issuedAt);
+      this.expirationTime = toISOStringOrUndefined(parsed.expirationTime);
+      this.notBefore = toISOStringOrUndefined(parsed.notBefore);
+      this.requestId = parsed.requestId;
+      this.resources = parsed.resources;
+      this.message = params;
       this.providerUrl = providerUrl;
+      this.provider = buildPublicClient(providerUrl, this.chainId);
       return;
     }
 
@@ -86,18 +135,11 @@ export class SIWENS extends SiweMessage {
       throw InvalidConfigurationException.domainRequired();
     }
 
-    let issuedAt = params.issuedAt;
-    let expirationTime = params.expirationTime;
-
-    if (params.ttl) {
-      checkTTL(params.ttl);
-      const {
-        issuedAt: issuedAtGenerated,
-        expirationTime: expirationTimeGenerated,
-      } = SIWENS.generateIssuedAndExpirationTime(params.ttl);
-      issuedAt = issuedAt || issuedAtGenerated;
-      expirationTime = expirationTime || expirationTimeGenerated;
-    }
+    checkTTL(params.ttl);
+    const {
+      issuedAt: issuedAtGenerated,
+      expirationTime: expirationTimeGenerated,
+    } = SIWENS.generateIssuedAndExpirationTime(params.ttl);
 
     checkDomainValid(params.ens);
 
@@ -106,46 +148,140 @@ export class SIWENS extends SiweMessage {
       params?.statement || ''
     );
 
-    super({
-      ...params,
-      statement,
-      version: params.version || '1',
-      issuedAt,
-      expirationTime,
-    });
+    this.scheme = params.scheme;
+    this.domain = params.domain;
+    this.address = viemGetAddress(params.address as string);
+    this.statement = statement;
+    this.uri = params.uri as string;
+    this.version = params.version || '1';
+    this.chainId = (params.chainId as number) ?? 1;
+    this.nonce = params.nonce || generateNonce();
+    this.issuedAt = params.issuedAt || issuedAtGenerated;
+    this.expirationTime = params.expirationTime || expirationTimeGenerated;
+    this.notBefore = params.notBefore;
+    this.requestId = params.requestId;
+    this.resources = params.resources;
     this.providerUrl = providerUrl;
     this.provider = buildPublicClient(providerUrl, this.chainId);
+    this.message = this.buildMessage();
+  }
+
+  toMessage(): string {
+    return this.message;
+  }
+
+  prepareMessage(): string {
+    return this.message;
   }
 
-  override async verify(
+  async verify(
     params: VerifyParams,
     opts?: VerifyOpts
   ): Promise<SiwensResponse> {
-    let verification: SiweResponse;
+    const suppress = opts?.suppressExceptions ?? false;
+    const data = this.toFields();
 
-    try {
-      const { signature, ...rest } = params;
-      const _tempParams = {
-        signature,
-        ...rest,
-      };
-      const lastByte = parseInt(signature.slice(-2), 16);
-      if (lastByte < 27) {
-        const adjustedV = (27 + (lastByte % 2)).toString(16).padStart(2, '0');
-        _tempParams['signature'] = signature.slice(0, -2) + adjustedV;
+    const computeEns = (): string | undefined => {
+      try {
+        return this.statement
+          ? toUnicode(extractDataFromStatement(this.statement).ens)
+          : undefined;
+      } catch {
+        return undefined;
       }
+    };
 
-      verification = await super.verify(_tempParams, opts);
-    } catch (e) {
-      const statement = e.data.statement;
-      const { ens } = extractDataFromStatement(statement);
-      throw {
-        ...e,
-        ens: toUnicode(ens),
+    const fail = (error: SiweError): SiwensResponse => {
+      const result: SiwensResponse = {
+        success: false,
+        data,
+        error,
+        ens: computeEns() as string,
       };
+      if (suppress) {
+        return result;
+      }
+      throw result;
+    };
+
+    // Normalize legacy `v` values (< 27) to canonical 27/28 before verifying.
+    let signature = params.signature;
+    const lastByte = parseInt(signature.slice(-2), 16);
+    if (lastByte < 27) {
+      const adjustedV = (27 + (lastByte % 2)).toString(16).padStart(2, '0');
+      signature = signature.slice(0, -2) + adjustedV;
     }
 
-    const statement = verification.data.statement;
+    // Field validation — mirrors `siwe`'s order and error types so the thrown
+    // shape is unchanged for consumers.
+    if (params.scheme && params.scheme !== this.scheme) {
+      return fail(
+        new SiweError(SiweErrorType.SCHEME_MISMATCH, params.scheme, this.scheme)
+      );
+    }
+    if (params.domain && params.domain !== this.domain) {
+      return fail(
+        new SiweError(SiweErrorType.DOMAIN_MISMATCH, params.domain, this.domain)
+      );
+    }
+    if (params.nonce && params.nonce !== this.nonce) {
+      return fail(
+        new SiweError(SiweErrorType.NONCE_MISMATCH, params.nonce, this.nonce)
+      );
+    }
+
+    const checkTime = new Date(params.time || new Date());
+    if (this.expirationTime) {
+      const expirationDate = new Date(this.expirationTime);
+      if (checkTime.getTime() >= expirationDate.getTime()) {
+        return fail(
+          new SiweError(
+            SiweErrorType.EXPIRED_MESSAGE,
+            `${checkTime.toISOString()} < ${expirationDate.toISOString()}`,
+            `${checkTime.toISOString()} >= ${expirationDate.toISOString()}`
+          )
+        );
+      }
+    }
+    if (this.notBefore) {
+      const notBefore = new Date(this.notBefore);
+      if (checkTime.getTime() < notBefore.getTime()) {
+        return fail(
+          new SiweError(
+            SiweErrorType.NOT_YET_VALID_MESSAGE,
+            `${checkTime.toISOString()} >= ${notBefore.toISOString()}`,
+            `${checkTime.toISOString()} < ${notBefore.toISOString()}`
+          )
+        );
+      }
+    }
+
+    // Signature verification — EOA recovery + EIP-1271 + ERC-6492 in a single
+    // viem call against the configured public client. A genuine signature
+    // mismatch resolves to `false`; operational errors (RPC/transport failures)
+    // are intentionally left to propagate rather than be masked as an invalid
+    // signature, so contract-wallet checks on a flaky RPC surface a real error.
+    const valid = await verifySiweMessage(this.provider, {
+      message: this.message,
+      signature: signature as `0x${string}`,
+      address: this.address as `0x${string}`,
+      ...(params.domain ? { domain: params.domain } : {}),
+      ...(params.nonce ? { nonce: params.nonce } : {}),
+      ...(params.scheme ? { scheme: params.scheme } : {}),
+      time: checkTime,
+    });
+
+    if (!valid) {
+      return fail(
+        new SiweError(
+          SiweErrorType.INVALID_SIGNATURE,
+          undefined,
+          `Resolved address to be ${this.address}`
+        )
+      );
+    }
+
+    const statement = this.statement;
     if (!statement) {
       throw InvalidStatementException.invalidStatement();
     }
@@ -154,7 +290,8 @@ export class SIWENS extends SiweMessage {
     await this.verifyEnsAddress(ens, this.address);
 
     return {
-      ...verification,
+      success: true,
+      data,
       ens,
     };
   }
@@ -169,10 +306,48 @@ export class SIWENS extends SiweMessage {
     };
   }
 
-  static generateNonce() {
+  static generateNonce(): string {
     return generateNonce();
   }
 
+  private toFields(): SiweMessageFields {
+    return {
+      scheme: this.scheme,
+      domain: this.domain,
+      address: this.address,
+      statement: this.statement,
+      uri: this.uri,
+      version: this.version,
+      chainId: this.chainId,
+      nonce: this.nonce,
+      issuedAt: this.issuedAt,
+      expirationTime: this.expirationTime,
+      notBefore: this.notBefore,
+      requestId: this.requestId,
+      resources: this.resources,
+    };
+  }
+
+  private buildMessage(): string {
+    return createSiweMessage({
+      ...(this.scheme ? { scheme: this.scheme } : {}),
+      domain: this.domain,
+      address: viemGetAddress(this.address),
+      ...(this.statement ? { statement: this.statement } : {}),
+      uri: this.uri,
+      version: this.version as '1',
+      chainId: this.chainId,
+      nonce: this.nonce,
+      ...(this.issuedAt ? { issuedAt: new Date(this.issuedAt) } : {}),
+      ...(this.expirationTime
+        ? { expirationTime: new Date(this.expirationTime) }
+        : {}),
+      ...(this.notBefore ? { notBefore: new Date(this.notBefore) } : {}),
+      ...(this.requestId ? { requestId: this.requestId } : {}),
+      ...(this.resources ? { resources: this.resources } : {}),
+    });
+  }
+
   private async verifyEnsAddress(ens: string, address: string) {
     const resolvedAddress = await this.provider.getEnsAddress({
       name: normalize(ens),
diff --git a/packages/@justaname.id/siwens/src/lib/types/index.ts b/packages/@justaname.id/siwens/src/lib/types/index.ts
new file mode 100644
index 00000000..97f5bb99
--- /dev/null
+++ b/packages/@justaname.id/siwens/src/lib/types/index.ts
@@ -0,0 +1,88 @@
+/**
+ * Local, ethers-free replacements for the SIWE types that used to be imported
+ * from the `siwe` package. Keeping the same shapes (and the same `SiweError`
+ * `type` strings) preserves the public API and the error contract that the
+ * SDK's sign-in flow and downstream consumers depend on.
+ */
+
+/** EIP-4361 message fields, mirroring the public surface of `siwe`'s SiweMessage. */
+export interface SiweMessageFields {
+  scheme?: string;
+  domain: string;
+  address: string;
+  statement?: string;
+  uri: string;
+  version: string;
+  chainId: number;
+  nonce: string;
+  issuedAt?: string;
+  expirationTime?: string;
+  notBefore?: string;
+  requestId?: string;
+  resources?: string[];
+}
+
+/** Result returned (or thrown) by a verification. */
+export interface SiweResponse {
+  success: boolean;
+  data: SiweMessageFields;
+  error?: SiweError;
+}
+
+/** Parameters accepted by `SIWENS.verify`. */
+export interface VerifyParams {
+  signature: string;
+  scheme?: string;
+  domain?: string;
+  nonce?: string;
+  time?: string;
+}
+
+/** Options accepted by `SIWENS.verify`. */
+export interface VerifyOpts {
+  suppressExceptions?: boolean;
+}
+
+/**
+ * Mirrors `siwe`'s SiweError so thrown/returned error shapes are unchanged.
+ */
+export class SiweError {
+  constructor(
+    public type: SiweErrorType,
+    public expected?: string,
+    public received?: string
+  ) {}
+}
+
+/**
+ * Possible message error types. Values are copied verbatim from `siwe` so any
+ * consumer matching on the message string keeps working.
+ */
+export enum SiweErrorType {
+  /** `expirationTime` is present and in the past. */
+  EXPIRED_MESSAGE = 'Expired message.',
+  /** `domain` is not a valid authority or is empty. */
+  INVALID_DOMAIN = 'Invalid domain.',
+  /** `scheme` don't match the scheme provided for verification. */
+  SCHEME_MISMATCH = 'Scheme does not match provided scheme for verification.',
+  /** `domain` don't match the domain provided for verification. */
+  DOMAIN_MISMATCH = 'Domain does not match provided domain for verification.',
+  /** `nonce` don't match the nonce provided for verification. */
+  NONCE_MISMATCH = 'Nonce does not match provided nonce for verification.',
+  /** `address` does not conform to EIP-55 or is not a valid address. */
+  INVALID_ADDRESS = 'Invalid address.',
+  /** `uri` does not conform to RFC 3986. */
+  INVALID_URI = 'URI does not conform to RFC 3986.',
+  /** `nonce` is smaller then 8 characters or is not alphanumeric */
+  INVALID_NONCE = 'Nonce size smaller then 8 characters or is not alphanumeric.',
+  /** `notBefore` is present and in the future. */
+  NOT_YET_VALID_MESSAGE = 'Message is not valid yet.',
+  /** Signature doesn't match the address of the message. */
+  INVALID_SIGNATURE = 'Signature does not match address of the message.',
+  /** `expirationTime`, `notBefore` or `issuedAt` not complient to ISO-8601. */
+  INVALID_TIME_FORMAT = 'Invalid time format.',
+  /** `version` is not 1. */
+  INVALID_MESSAGE_VERSION = 'Invalid message version.',
+  /** Thrown when some required field is missing. */
+  UNABLE_TO_PARSE = 'Unable to parse the message.',
+}
diff --git a/packages/@justaname.id/siwens/src/lib/utils/generateNonce/index.ts b/packages/@justaname.id/siwens/src/lib/utils/generateNonce/index.ts
new file mode 100644
index 00000000..dcc32914
--- /dev/null
+++ b/packages/@justaname.id/siwens/src/lib/utils/generateNonce/index.ts
@@ -0,0 +1,19 @@
+import { randomStringForEntropy } from '@stablelib/random';
+
+/**
+ * Generates a cryptographically-secure, EIP-4361-compliant nonce.
+ *
+ * This mirrors `siwe`'s `generateNonce` (96 bits of entropy via a CSPRNG) so we
+ * keep identical nonce strength/format after dropping the `siwe` dependency.
+ * Intentionally NOT viem's `generateSiweNonce`, which is backed by `Math.random`
+ * and would be a security regression.
+ *
+ * @returns {string} A randomly generated alphanumeric nonce.
+ */
+export function generateNonce(): string {
+  const nonce = randomStringForEntropy(96);
+  if (!nonce || nonce.length < 8) {
+    throw new Error('Error during nonce creation.');
+  }
+  return nonce;
+}
diff --git a/packages/@justaname.id/siwens/src/lib/utils/index.ts b/packages/@justaname.id/siwens/src/lib/utils/index.ts
index 4f35d9ee..b20631c5 100644
--- a/packages/@justaname.id/siwens/src/lib/utils/index.ts
+++ b/packages/@justaname.id/siwens/src/lib/utils/index.ts
@@ -1,3 +1,4 @@
 export * from './checkTTL'
 export * from './checkDomainValid'
-export * from './signInStatementHelpers'
\ No newline at end of file
+export * from './signInStatementHelpers'
+export * from './generateNonce'
\ No newline at end of file
diff --git a/packages/@justaname.id/siwens/src/test/siwens.format.spec.ts b/packages/@justaname.id/siwens/src/test/siwens.format.spec.ts
new file mode 100644
index 00000000..16e1cb68
--- /dev/null
+++ b/packages/@justaname.id/siwens/src/test/siwens.format.spec.ts
@@ -0,0 +1,119 @@
+import { SIWENS, SiweErrorType } from '../';
+
+/**
+ * CI-safe tests (no RPC required). These lock the EIP-4361 message format to be
+ * byte-identical to what `siwe` produced before the viem migration, and verify
+ * that field-mismatch checks throw the same `SiweError` types. Signature
+ * verification (which needs a provider) is covered by the integration tests in
+ * siwens.spec.ts.
+ */
+
+const ADDRESS = '0x59c44836630760F97b74b569B379ca94c37B93ca';
+const DUMMY_SIGNATURE = '0x' + '00'.repeat(65);
+
+// Golden string captured from `siwe`'s SiweMessage.prepareMessage() for the
+// SIWENS object-construction inputs below (statement from `alice.eth`).
+const GOLDEN_MESSAGE = `localhost wants you to sign in with your Ethereum account:
+0x59c44836630760F97b74b569B379ca94c37B93ca
+
+I am signing in with my ENS: alice.eth
+
+URI: http://localhost:3333
+Version: 1
+Chain ID: 1
+Nonce: abcdef1234567890
+Issued At: 2024-01-01T00:00:00.000Z
+Expiration Time: 2024-01-01T00:01:00.000Z`;
+
+const baseParams = {
+  domain: 'localhost',
+  address: ADDRESS,
+  uri: 'http://localhost:3333',
+  version: '1',
+  nonce: 'abcdef1234567890',
+  chainId: 1,
+  ttl: 60 * 1000,
+  ens: 'alice.eth',
+  issuedAt: '2024-01-01T00:00:00.000Z',
+  expirationTime: '2024-01-01T00:01:00.000Z',
+};
+
+describe('SIWENS message format (golden)', () => {
+  it('builds a byte-identical EIP-4361 message', () => {
+    const siwens = new SIWENS({ params: { ...baseParams } });
+    expect(siwens.prepareMessage()).toBe(GOLDEN_MESSAGE);
+    expect(siwens.toMessage()).toBe(GOLDEN_MESSAGE);
+  });
+
+  it('round-trips when re-parsed from the string form', () => {
+    const message = new SIWENS({ params: { ...baseParams } }).prepareMessage();
+    const reparsed = new SIWENS({
+      params: message,
+      providerUrl: 'http://127.0.0.1:1',
+    });
+    expect(reparsed.address).toBe(ADDRESS);
+    expect(reparsed.chainId).toBe(1);
+    expect(reparsed.domain).toBe('localhost');
+    expect(reparsed.nonce).toBe('abcdef1234567890');
+    expect(reparsed.statement).toBe('I am signing in with my ENS: alice.eth');
+  });
+});
+
+describe('SIWENS.verify field validation (no RPC)', () => {
+  it('throws DOMAIN_MISMATCH with the preserved error shape', async () => {
+    const siwens = new SIWENS({ params: { ...baseParams } });
+    await expect(
+      siwens.verify({ signature: DUMMY_SIGNATURE, domain: 'evil.com' })
+    ).rejects.toMatchObject({
+      success: false,
+      error: { type: SiweErrorType.DOMAIN_MISMATCH },
+      ens: 'alice.eth',
+    });
+  });
+
+  it('throws NONCE_MISMATCH', async () => {
+    const siwens = new SIWENS({ params: { ...baseParams } });
+    await expect(
+      siwens.verify({ signature: DUMMY_SIGNATURE, nonce: 'someOtherNonce123' })
+    ).rejects.toMatchObject({
+      error: { type: SiweErrorType.NONCE_MISMATCH },
+    });
+  });
+
+  it('throws EXPIRED_MESSAGE when the message is past expiry', async () => {
+    const siwens = new SIWENS({
+      params: {
+        ...baseParams,
+        issuedAt: '2020-01-01T00:00:00.000Z',
+        expirationTime: '2020-01-01T00:01:00.000Z',
+      },
+    });
+    await expect(
+      siwens.verify({ signature: DUMMY_SIGNATURE })
+    ).rejects.toMatchObject({
+      error: { type: SiweErrorType.EXPIRED_MESSAGE },
+    });
+  });
+
+  it('returns a failure result instead of throwing when suppressExceptions is set', async () => {
+    const siwens = new SIWENS({ params: { ...baseParams } });
+    const result = await siwens.verify(
+      { signature: DUMMY_SIGNATURE, domain: 'evil.com' },
+      { suppressExceptions: true }
+    );
+    expect(result.success).toBe(false);
+    expect(result.error?.type).toBe(SiweErrorType.DOMAIN_MISMATCH);
+    expect(result.ens).toBe('alice.eth');
+  });
+});
+
+describe('generateNonce', () => {
+  it('produces alphanumeric nonces of sufficient length', () => {
+    const nonce = SIWENS.generateNonce();
+    expect(nonce).toMatch(/^[a-zA-Z0-9]{8,}$/);
+  });
+
+  it('produces a different nonce each call', () => {
+    expect(SIWENS.generateNonce()).not.toBe(SIWENS.generateNonce());
+  });
+});
diff --git a/yarn.lock b/yarn.lock
index d9a439d4..92773d43 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -4487,7 +4487,6 @@ __metadata:
     jest: "npm:^29.4.1"
     qs: "npm:6.12.0"
   peerDependencies:
-    siwe: ">=2.0.0"
     viem: ^2.48.0
   languageName: unknown
   linkType: soft
@@ -4496,9 +4495,9 @@ __metadata:
   version: 0.0.0-use.local
   resolution: "@justaname.id/siwens@workspace:packages/@justaname.id/siwens"
   dependencies:
+    "@stablelib/random": "npm:^1.0.2"
     punycode: "npm:^2.3.1"
   peerDependencies:
-    siwe: ">=2.0.0"
     viem: ^2.48.0
   languageName: unknown
   linkType: soft
@@ -5640,7 +5639,7 @@ __metadata:
   languageName: node
   linkType: hard
 
-"@noble/hashes@npm:1.7.1, @noble/hashes@npm:^1.1.2, @noble/hashes@npm:^1.3.1, @noble/hashes@npm:^1.3.2, @noble/hashes@npm:^1.4.0, @noble/hashes@npm:^1.5.0, @noble/hashes@npm:~1.7.1":
+"@noble/hashes@npm:1.7.1, @noble/hashes@npm:^1.3.1, @noble/hashes@npm:^1.3.2, @noble/hashes@npm:^1.4.0, @noble/hashes@npm:^1.5.0, @noble/hashes@npm:~1.7.1":
   version: 1.7.1
   resolution: "@noble/hashes@npm:1.7.1"
   checksum: 10c0/2f8ec0338ccc92b576a0f5c16ab9c017a3a494062f1fbb569ae641c5e7eab32072f9081acaa96b5048c0898f972916c818ea63cbedda707886a4b5ffcfbf94e3
@@ -9277,18 +9276,6 @@ __metadata:
   languageName: node
   linkType: hard
 
-"@spruceid/siwe-parser@npm:^2.1.2":
-  version: 2.1.2
-  resolution: "@spruceid/siwe-parser@npm:2.1.2"
-  dependencies:
-    "@noble/hashes": "npm:^1.1.2"
-    apg-js: "npm:^4.3.0"
-    uri-js: "npm:^4.4.1"
-    valid-url: "npm:^1.0.9"
-  checksum: 10c0/79005ae8978b9dd0c1ece949dbc2294d6a641db757c14ae0864b6803358cc498bac882d8031e656b4dbf3e838be043ce6517c857b6e2df26a1e8922baeb2c07d
-  languageName: node
-  linkType: hard
-
 "@stablelib/binary@npm:^1.0.1":
   version: 1.0.1
   resolution: "@stablelib/binary@npm:1.0.1"
@@ -9305,7 +9292,7 @@ __metadata:
   languageName: node
   linkType: hard
 
-"@stablelib/random@npm:^1.0.1":
+"@stablelib/random@npm:^1.0.2":
   version: 1.0.2
   resolution: "@stablelib/random@npm:1.0.2"
   dependencies:
@@ -14270,13 +14257,6 @@ __metadata:
   languageName: node
   linkType: hard
 
-"apg-js@npm:^4.3.0":
-  version: 4.4.0
-  resolution: "apg-js@npm:4.4.0"
-  checksum: 10c0/b3e60e2ba8b25fe1c9fcc648f43b98f02f0eff3bbd593fd2866302fe57b1b7840ee9be894ebed6214876a6feecd543cc717d7b68351bf2df831db110ae01e6bb
-  languageName: node
-  linkType: hard
-
 "app-root-dir@npm:^1.0.2":
   version: 1.0.2
   resolution: "app-root-dir@npm:1.0.2"
@@ -25427,7 +25407,6 @@ __metadata:
     rollup-plugin-tailwindcss: "npm:1.0.0"
     rollup-plugin-typescript2: "npm:0.36.0"
     rollup-preserve-directives: "npm:1.1.1"
-    siwe: "npm:2.3.2"
     storybook: "npm:8.2.8"
     tailwind-merge: "npm:2.5.2"
     tailwindcss: "npm:3.4.3"
@@ -33040,20 +33019,6 @@ __metadata:
   languageName: node
   linkType: hard
 
-"siwe@npm:2.3.2":
-  version: 2.3.2
-  resolution: "siwe@npm:2.3.2"
-  dependencies:
-    "@spruceid/siwe-parser": "npm:^2.1.2"
-    "@stablelib/random": "npm:^1.0.1"
-    uri-js: "npm:^4.4.1"
-    valid-url: "npm:^1.0.9"
-  peerDependencies:
-    ethers: ^5.6.8 || ^6.0.8
-  checksum: 10c0/05ee09cdabef72a8ec54ffe24e517c386eb49bb6385ffc7ec159e266b3661a98405ca88b8e75278b376754e943a5118790c2add98b5012e1c4ec13bce4e6ee03
-  languageName: node
-  linkType: hard
-
 "slash@npm:3.0.0, slash@npm:^3.0.0":
   version: 3.0.0
   resolution: "slash@npm:3.0.0"
@@ -35798,7 +35763,7 @@ __metadata:
   languageName: node
   linkType: hard
 
-"uri-js@npm:^4.2.2, uri-js@npm:^4.4.1":
+"uri-js@npm:^4.2.2":
   version: 4.4.1
   resolution: "uri-js@npm:4.4.1"
   dependencies:
@@ -35998,13 +35963,6 @@ __metadata:
   languageName: node
   linkType: hard
 
-"valid-url@npm:^1.0.9":
-  version: 1.0.9
-  resolution: "valid-url@npm:1.0.9"
-  checksum: 10c0/3995e65f9942dbcb1621754c0f9790335cec61e9e9310c0a809e9ae0e2ae91bb7fc6a471fba788e979db0418d9806639f681ecebacc869bc8c3de88efa562ee6
-  languageName: node
-  linkType: hard
-
 "validate-npm-package-license@npm:^3.0.1, validate-npm-package-license@npm:^3.0.4":
   version: 3.0.4
   resolution: "validate-npm-package-license@npm:3.0.4"