diff --git a/src/core/exception/exception.normalizer.test.ts b/src/core/exception/exception.normalizer.test.ts
index c288475561..f1b3ee95ad 100644
--- a/src/core/exception/exception.normalizer.test.ts
+++ b/src/core/exception/exception.normalizer.test.ts
@@ -1,5 +1,6 @@
 // eslint-disable-next-line no-restricted-imports,@seedcompany/no-restricted-imports
 import * as Nest from '@nestjs/common';
+import * as Fastify from 'fastify';
 import { InputException, ServerException } from '~/common';
 import { ConstraintError } from '../database';
 import { ExceptionNormalizer } from './exception.normalizer';
@@ -10,6 +11,23 @@ describe('ExceptionNormalizer', () => {
   const orig = sut.normalize.bind(sut);
   sut.normalize = (...args) => JSON.parse(JSON.stringify(orig(...args)));
 
+  describe('Fastify', () => {
+    it('Client', () => {
+      const ex = new Fastify.errorCodes.FST_ERR_CTP_BODY_TOO_LARGE();
+      const res = sut.normalize({ ex });
+      expect(res.message).toEqual('Request body is too large');
+      expect(res.code).toEqual('FST_ERR_CTP_BODY_TOO_LARGE');
+      expect(res.codes).toEqual(['FST_ERR_CTP_BODY_TOO_LARGE', 'Client']);
+    });
+    it('Server', () => {
+      const ex = new Fastify.errorCodes.FST_ERR_HOOK_INVALID_TYPE();
+      const res = sut.normalize({ ex });
+      expect(res.message).toEqual('The hook name must be a string');
+      expect(res.code).toEqual('FST_ERR_HOOK_INVALID_TYPE');
+      expect(res.codes).toEqual(['FST_ERR_HOOK_INVALID_TYPE', 'Server']);
+    });
+  });
+
   describe('HttpException', () => {
     it('simple', () => {
       const ex = new Nest.NotFoundException();
diff --git a/src/core/exception/exception.normalizer.ts b/src/core/exception/exception.normalizer.ts
index 5af7e24cdd..8f2055c6e5 100644
--- a/src/core/exception/exception.normalizer.ts
+++ b/src/core/exception/exception.normalizer.ts
@@ -174,6 +174,15 @@ export class ExceptionNormalizer {
       return { codes: ['GraphQL', 'Server'] };
     }
 
+    // Fastify convention
+    if ('statusCode' in ex && typeof ex.statusCode === 'number') {
+      const codes = [
+        'code' in ex && typeof ex.code === 'string' ? ex.code : undefined,
+        ex.statusCode < 500 ? 'Client' : 'Server',
+      ];
+      return { codes };
+    }
+
     // Fallback to generic Error
     return { codes: ['Server'] };
   }