Why I Chose Fastify Over Express

When starting a new Node.js backend project, the first question is always: Express, Fastify, or something else?

The Case for Fastify

After years of using Express, I switched to Fastify and haven't looked back. Here's why:

Performance

Fastify is significantly faster than Express in benchmarks — we're talking 2-3x on some routes. For a high-traffic API, this matters.

Schema Validation

Built-in JSON Schema validation means I can declare my request/response shapes and get automatic validation + serialization for free.

fastify.get('/users/:id', {
  schema: {
    params: {
      type: 'object',
      properties: {
        id: { type: 'string' }
      }
    }
  }
}, async (request, reply) => {
  // request.params.id is validated
})

Plugin System

The Fastify plugin system with fastify-plugin is more organized than Express middleware.

When Express Still Wins

Express has a much larger ecosystem and more tutorials. If you're building something quick or need a specific middleware, Express might still be the right choice.