Does Fastify Work With TypeORM?

Fully CompatibleLast verified: 2026-02-20

Fastify and TypeORM work excellently together, with TypeORM handling database operations while Fastify manages HTTP routing and lifecycle.

Quick Facts

Compatibility

full

Setup Difficulty

Easy

Official Integration

No — community maintained

Confidence

high

Minimum Versions

Fastify: 3.0.0

TypeORM: 0.2.0

How Fastify Works With TypeORM

Fastify and TypeORM integrate seamlessly because they operate at different layers of your application. TypeORM manages your database connection pool and entities independently, while Fastify provides the HTTP server and request handling. You typically initialize TypeORM's DataSource on Fastify startup using hooks, then inject repositories into your route handlers. The combination is lightweight and performant—both frameworks prioritize speed and minimal overhead. Developers commonly register TypeORM as a Fastify plugin or decorator to access the DataSource across routes. Connection pooling is handled by TypeORM, which works efficiently with Fastify's async request pipeline. The main consideration is proper lifecycle management: initialize TypeORM before Fastify starts listening, and gracefully close the database connection when the server shuts down.

Best Use Cases

→Building REST APIs with full type safety using TypeScript entities and Fastify's type inference

→Microservices requiring a lightweight HTTP framework paired with robust database abstraction

→Real-time applications where Fastify's low overhead matters and TypeORM handles complex queries

→Multi-database applications where TypeORM's database-agnostic approach suits Fastify's flexibility

Quick Setup

bash

npm install fastify typeorm reflect-metadata pg

typescript

import 'reflect-metadata';
import Fastify from 'fastify';
import { DataSource } from 'typeorm';
import { User } from './entities/User';

const dataSource = new DataSource({
  type: 'postgres',
  host: 'localhost',
  port: 5432,
  database: 'mydb',
  synchronize: true,
  entities: [User],
});

const fastify = Fastify({ logger: true });

fastify.addHook('onReady', async () => {
  await dataSource.initialize();
});

fastify.get('/users/:id', async (request, reply) => {
  const user = await dataSource
    .getRepository(User)
    .findOneBy({ id: parseInt(request.params.id) });
  return user || reply.code(404).send('Not found');
});

fastify.listen({ port: 3000 }, (err) => {
  if (err) throw err;
});

Known Issues & Gotchas

critical

TypeORM DataSource not initialized before routes execute

Fix: Use Fastify's onReady hook or await DataSource.initialize() before registering routes. Wrap route handlers in a check or use plugin registration order.

warning

Connection pool exhaustion under high load

Fix: Tune TypeORM's pool size in DataSourceOptions.max setting. Monitor active connections and adjust based on concurrent request patterns.

warning

Lazy loading relations in async context can cause issues

Fix: Use eager loading or explicit relation loading with QueryBuilder. Avoid lazy loading across async boundaries in Fastify handlers.

info

Request-scoped transaction management complexity

Fix: Use TypeORM's QueryRunner for request-scoped transactions, or leverage Fastify decorators to attach transaction context to each request.

Alternatives

•Express.js + TypeORM: More mature ecosystem but slower than Fastify
•Fastify + Prisma: Modern alternative with better developer experience, but less flexible than TypeORM
•NestJS + TypeORM: Opinionated framework bundling both, heavier but highly structured

Resources

docsFastify Official Documentation docsTypeORM Official Documentation githubFastify with TypeORM Example Repository tutorialTypeORM DataSource Guide

Related Compatibility Guides

PlanetScale + TypeORM NestJS + TypeORM Fastify + PostgreSQL Fastify + UploadThing Fastify + Paddle Fastify + Prisma

Explore more compatibility guides

All Fastify combos All TypeORM combos