diff --git a/src/index.ts b/src/index.ts
index 034d736..e0eaf7e 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -4,7 +4,7 @@ import { Elysia, t } from 'elysia';
 import config from './config';
 import serverConfig from './config-server';
 import { databaseService } from './database-service';
-import { createInvoiceForSparkAddress, initializeSparkWallet } from './spark-service';
+import { createInvoiceForSparkAddress, initializeSparkWallet, isSparkAddress } from './spark-service';
 
 const pckg = require('../package.json');
 
@@ -87,13 +87,19 @@ const app = new Elysia(serverConfig.elysia)
             } = query;
 
             // Validate required parameters
-            if (!amount) {
+            if (!amount || !username) {
                 throw new Error('Missing required parameters');
             }
 
-            const sparkAddress = databaseService.getSparkAddressByUsername(username);
-            if (!sparkAddress) {
-                return { status: 'ERROR', reason: 'Username not found' };
+            let sparkAddress = username;
+
+            if (!isSparkAddress(username)) {
+                const sparkFromDatabase = databaseService.getSparkAddressByUsername(username);
+                if (!sparkFromDatabase) {
+                    return { status: 'ERROR', reason: 'Username not found' };
+                }
+
+                sparkAddress = sparkFromDatabase;
             }
 
             // FIXME: use the username to get the spark address
diff --git a/src/spark-service.ts b/src/spark-service.ts
index e1b1970..a33396f 100644
--- a/src/spark-service.ts
+++ b/src/spark-service.ts
@@ -52,6 +52,15 @@ export async function createInvoiceForSparkAddress(sparkAddress: string, amountS
     return invoice.invoice.encodedInvoice;
 }
 
+export function isSparkAddress(address: string): boolean {
+    try {
+        bech32m.decode(address);
+        return address.startsWith('spark1');
+    } catch (_) {
+        return false;
+    }
+}
+
 function convert5BitArrayToHex(words: number[]) {
     let bits = 0;
     let value = 0;
diff --git a/test/spark-service.test.ts b/test/spark-service.test.ts
new file mode 100644
index 0000000..edbed06
--- /dev/null
+++ b/test/spark-service.test.ts
@@ -0,0 +1,17 @@
+import { describe, expect, it } from 'bun:test'
+import { isSparkAddress } from '../src/spark-service'
+
+describe('SparkService', () => {
+    describe('isSparkAddress', () => {
+        it('returns true for valid bech32m addresses', () => {
+            expect(isSparkAddress('bc1pm6lqlel3qxefsx0v39nshtghasvvp6ghn3e5hd5q280j5m9h7csqrkzssu')).toBe(false);        
+            expect(isSparkAddress('spark1qw2e3r4t5y6u7i8o9p0')).toBe(false);        
+            expect(isSparkAddress('invalid-address')).toBe(false)
+            expect(isSparkAddress('')).toBe(false)
+            expect(isSparkAddress('123456')).toBe(false)
+
+            expect(isSparkAddress('spark1pgssxlr63wd3gyt99uzn9nwmjdncg6lfw6vamkuqf3u7aafuyzds9ny3u9ftwa')).toBe(true);
+        })
+    })
+})
+