diff --git a/src/main.ts b/src/main.ts
index ed14af0..1b11c4b 100644
--- a/src/main.ts
+++ b/src/main.ts
@@ -1,3 +1,6 @@
+// Patch BigInt JSON serialization (Prisma returns BigInt for BigInt columns)
+;(BigInt.prototype as any).toJSON = function () { return Number(this) };
+
 import { NestFactory } from '@nestjs/core';
 import { SwaggerModule, DocumentBuilder } from '@nestjs/swagger';
 import { AppModule } from './app.module';