diff --git a/backend/src/middleware/errorHandler.js b/backend/src/middleware/errorHandler.js
index 67227ba..ba10080 100644
--- a/backend/src/middleware/errorHandler.js
+++ b/backend/src/middleware/errorHandler.js
@@ -214,6 +214,16 @@ function formatErrorResponse(err, req) {
   return response;
 }
 
+/**
+ * Attach request ID to error response
+ */
+export function attachRequestIdToError(err, req) {
+  if (!err.requestId) {
+    err.requestId = req.id || 'unknown';
+  }
+  return err;
+}
+
 /**
  * Centralized error handling middleware
  */
@@ -223,6 +233,9 @@ export function errorHandler(err, req, res, next) {
     return next(err);
   }
 
+  // Attach request ID to error
+  attachRequestIdToError(err, req);
+
   // Default error values
   let statusCode = err.statusCode || 500;
   let code = err.code || ErrorCodes.INTERNAL_ERROR;
@@ -327,4 +340,5 @@ export default {
   createValidationError,
   createStellarError,
   generateRequestId,
+  attachRequestIdToError,
 };
diff --git a/backend/src/middleware/securityHeaders.js b/backend/src/middleware/securityHeaders.js
index 7cf966e..acb45a5 100644
--- a/backend/src/middleware/securityHeaders.js
+++ b/backend/src/middleware/securityHeaders.js
@@ -28,7 +28,11 @@ export function helmetMiddleware() {
         ].filter(Boolean),
         styleSrc: ["'self'", "'unsafe-inline'"],
         imgSrc: ["'self'", "data:", "https:"],
-        connectSrc: ["'self'", "https://horizon.stellar.org", "https://horizon-testnet.stellar.org"],
+        connectSrc: [
+          "'self'",
+          "https://horizon.stellar.org",
+          "https://horizon-testnet.stellar.org",
+        ],
         fontSrc: ["'self'", "https:", "data:"],
         objectSrc: ["'none'"],
         mediaSrc: ["'self'"],
diff --git a/backend/src/middleware/validate.js b/backend/src/middleware/validate.js
index c1b0354..aab185d 100644
--- a/backend/src/middleware/validate.js
+++ b/backend/src/middleware/validate.js
@@ -83,7 +83,24 @@ export const rules = {
       .isFloat({ gt: 0 })
       .withMessage('Amount must be a positive number')
       .isLength({ max: 20 })
-      .withMessage('Amount too long'),
+      .withMessage('Amount too long')
+      .custom((amount) => {
+        // Normalize to fixed-decimal string with max 7 decimal places
+        const parsed = parseFloat(amount);
+        if (isNaN(parsed)) throw new Error('Amount must be a valid number');
+        
+        const normalized = parsed.toFixed(7);
+        const decimalPlaces = normalized.split('.')[1].replace(/0+$/, '').length;
+        
+        if (decimalPlaces > 7) {
+          throw new Error('Amount cannot have more than 7 decimal places');
+        }
+        return true;
+      })
+      .customSanitizer((amount) => {
+        // Normalize to fixed-decimal string with max 7 decimal places
+        return parseFloat(amount).toFixed(7);
+      }),
     body('assetCode')
       .optional()
       .trim()
@@ -209,7 +226,24 @@ export const rules = {
       .isFloat({ gt: 0 })
       .withMessage('Amount must be a positive number')
       .isLength({ max: 20 })
-      .withMessage('Amount too long'),
+      .withMessage('Amount too long')
+      .custom((amount) => {
+        // Normalize to fixed-decimal string with max 7 decimal places
+        const parsed = parseFloat(amount);
+        if (isNaN(parsed)) throw new Error('Amount must be a valid number');
+        
+        const normalized = parsed.toFixed(7);
+        const decimalPlaces = normalized.split('.')[1].replace(/0+$/, '').length;
+        
+        if (decimalPlaces > 7) {
+          throw new Error('Amount cannot have more than 7 decimal places');
+        }
+        return true;
+      })
+      .customSanitizer((amount) => {
+        // Normalize to fixed-decimal string with max 7 decimal places
+        return parseFloat(amount).toFixed(7);
+      }),
     body('assetCode')
       .optional()
       .trim()