NestJS vs Express vs Fastify: Which Should You Use in 2026?

Express — The Reliable Old Guard

Express handles ~15,000–20,000 requests/sec in benchmarks. Fast enough for most apps, but its middleware pipeline adds overhead on every request. No built-in TypeScript, no structure — everything is on you.

NestJS (on Express) — Structured but Same Speed

By default, NestJS runs on Express under the hood. You get all the DI, decorators, and module system — but performance is identical to Express. The architecture wins, not the throughput.

NestJS + Fastify — The Real Winner in 2026

Swap Express for Fastify in NestJS with two lines of code. Fastify handles ~30,000–35,000 requests/sec — roughly 2x Express — thanks to its optimized JSON serialization and schema-based routing. You keep all of NestJS's architecture, and gain serious throughput. (Results vary by hardware, payload, and test setup — always benchmark for your specific workload.)

Express at Scale — The Hidden Cost

Express scales horizontally fine, but your architecture doesn't scale with your team. There's no enforced module system, no DI container, no standard pattern. At 5+ developers, Express codebases become a convention war. You end up building NestJS manually, badly.

NestJS + Fastify at Scale

NestJS enforces domain boundaries through Modules. Pair it with Fastify's throughput and you get both organizational scale (teams working independently) and infrastructure scale (high-traffic APIs). NestJS also natively supports microservices, gRPC, WebSockets, and message queues — without reaching for separate frameworks.

Default NestJS (Express)

import { NestFactory } from '@nestjs/core';
import { AppModule } from './app.module';

async function bootstrap() {
  const app = await NestFactory.create(AppModule);
  await app.listen(3000);
}
bootstrap();

NestJS + Fastify (2 line change)

import { NestFactory } from '@nestjs/core';
import { FastifyAdapter, NestFastifyApplication } from '@nestjs/platform-fastify';
import { AppModule } from './app.module';

async function bootstrap() {
  const app = await NestFactory.create<NestFastifyApplication>(
    AppModule,
    new FastifyAdapter()
  );
  await app.listen(3000);
}
bootstrap();