Fastify's plugin architecture and JSON Schema validation made it a popular choice for Node.js backends. But as TypeScript adoption has grown, many teams find themselves fighting Fastify's design rather than benefiting from it. JSON Schema definitions are verbose, the plugin lifecycle has a learning curve, and you still need to wire up your own infrastructure, observability, and deployment.

If you're evaluating what comes next, this guide covers five Fastify alternatives worth considering in 2026. Each one takes a different approach to the problems Fastify solves, and some go further by handling infrastructure and observability too.

For a broader comparison, see our Best TypeScript Backend Frameworks guide.

Fastify Alternatives: An Overview

Encore.ts (Recommended)

Encore.ts approaches backend development differently from Fastify. Instead of defining JSON Schemas alongside your routes, you write standard TypeScript types and Encore validates requests at compile time. Instead of configuring plugins for databases, queues, and caching, you declare infrastructure as TypeScript objects and Encore provisions them automatically during local development.

The framework runs on a Rust-based runtime that handles HTTP parsing, validation, and I/O outside the Node.js event loop. This means you get significantly better performance than Fastify without writing any optimization code. For teams moving from Fastify, the shift from JSON Schema to TypeScript types alone removes a lot of boilerplate.

import { api } from "encore.dev/api";
import { SQLDatabase } from "encore.dev/storage/sqldb";

const db = new SQLDatabase("users", { migrations: "./migrations" });

interface User {
  id: number;
  name: string;
  email: string;
}

export const getUser = api(
  { method: "GET", path: "/users/:id", expose: true },
  async ({ id }: { id: number }): Promise<User> => {
    return await db.queryRow<User>`SELECT * FROM users WHERE id = ${id}`;
  }
);

Compare this with Fastify's equivalent, which requires separate JSON Schema definitions for params, response body, and serialization. In Encore, the TypeScript types are the schema. When you change a field name or add a new property to your interface, the validation and documentation update automatically. In Fastify, you'd need to update the JSON Schema, the TypeScript type, and potentially the serialization schema separately.

Key Features

• Type-safe request validation using standard TypeScript types
• Infrastructure primitives (databases, Pub/Sub, cron, caching) with automatic local provisioning
• Type-safe service-to-service communication with generated clients
• Built-in distributed tracing across services
• Service catalog and auto-generated API documentation
• Streaming APIs with WebSocket support
• Rust-based runtime for high throughput

Benefits

Coming from Fastify, the biggest quality-of-life improvement is removing the JSON Schema layer. You define a TypeScript interface once and it handles validation, serialization, and documentation. No more maintaining parallel type definitions and schemas.

Infrastructure automation is the other major difference. Fastify requires you to configure database connections, set up message queues, and manage Docker Compose files for local development. Encore provisions all of this automatically when you declare the resource in code.

Built-in distributed tracing means you see how requests flow through services without configuring Jaeger, OpenTelemetry, or any other observability stack. This is something Fastify teams typically spend weeks setting up. Encore also generates a service catalog that stays in sync with your code, giving you a live map of all your services, their APIs, and how they communicate.

Good to Know

Encore provides built-in primitives for databases, Pub/Sub, caching, and cron jobs instead of a plugin architecture. If your team has invested in custom Fastify plugins, check whether Encore's primitives cover those use cases or use standard npm libraries alongside them. You can mix Encore's built-in features with any npm package.

When to Consider Encore.ts

Consider Encore when you want to stop maintaining JSON Schema definitions alongside TypeScript types, when you're building multiple services that need to communicate, when you want infrastructure provisioned automatically in local development, or when observability matters and you don't want to configure it yourself. It's also a strong fit if you want infrastructure-aware code that AI agents can generate and deploy with guardrails.

For a detailed head-to-head, see our Fastify vs Encore.ts comparison.

Try Encore.ts

You can get started with Encore in minutes:

curl -L https://encore.dev/install.sh | bash
encore app create my-app
cd my-app
encore run

See the Encore.ts documentation for more details, follow the REST API tutorial to build a complete application, or check out Encore AI Integration for using Encore with AI coding agents.

Express.js

Express is the most established Node.js framework, and many Fastify users originally migrated from Express. Going back might seem counterintuitive, but Express has its merits for certain situations. The ecosystem is unmatched, the API is familiar to nearly every Node.js developer, and Express 5 has brought improvements to error handling and async support.

That said, the reasons you left Express for Fastify likely still apply. Express doesn't provide built-in validation, TypeScript support is bolted on, and you'll need middleware for most production requirements. Where Fastify gave you JSON Schema validation and a plugin lifecycle, Express gives you freedom and expects you to bring your own everything.

import express from 'express';
import { z } from 'zod';

const app = express();
app.use(express.json());

const UserParams = z.object({ id: z.string() });

app.get('/users/:id', async (req, res) => {
  const { id } = UserParams.parse(req.params);
  const user = await getUserById(id);
  res.json(user);
});

app.listen(3000);

Key Features

• Minimal core with the largest middleware ecosystem in Node.js
• Flexible routing with support for all HTTP methods
• Template engine support for server-rendered applications
• Widely understood API that most Node.js developers already know

Benefits

Express is the safe, conservative choice. If you're building a simple API and don't need schema validation or infrastructure automation, Express gets out of your way. The ecosystem means you can find middleware for nearly any requirement.

Limitations

No built-in validation, no TypeScript-first design, no infrastructure management. You'll need to add validation libraries, configure your own observability, and manage infrastructure separately. Performance is also lower than Fastify and significantly lower than Encore.ts. Error handling in async routes still requires careful attention, and the middleware execution model can lead to subtle ordering bugs in larger applications.

When to Consider Express

Consider Express when you need maximum flexibility, when your team is deeply familiar with the Express ecosystem, or when you're building a simple API where the overhead of more opinionated frameworks isn't justified.

For a deeper look, see our Express.js vs Encore.ts comparison.

NestJS

NestJS brings Angular-style architecture to the backend. If you left Fastify because you wanted more structure, NestJS provides it in abundance. The framework enforces consistent code organization through modules, controllers, and providers, with a dependency injection system that makes testing straightforward.

NestJS can actually use Fastify as its underlying HTTP adapter, so the transition can be incremental. But the real value of NestJS is the architectural patterns it enforces, not the HTTP layer underneath. Where Fastify organizes code through plugins, NestJS organizes code through modules and dependency injection. The tradeoff is more boilerplate per feature, but more consistency across a large codebase.

import { Controller, Get, Param } from '@nestjs/common';
import { UsersService } from './users.service';

@Controller('users')
export class UsersController {
  constructor(private readonly usersService: UsersService) {}

  @Get(':id')
  findOne(@Param('id') id: string) {
    return this.usersService.findOne(id);
  }
}

Key Features

• Angular-inspired module architecture with dependency injection
• Comprehensive decorator-based validation via class-validator
• First-class GraphQL and WebSocket support
• Microservices patterns with multiple transport layers
• Can use Express or Fastify as HTTP adapter

Benefits

NestJS provides strong guardrails for large teams. The enforced architecture means code stays consistent as the team and codebase grow. The comprehensive feature set means you rarely need to look outside the framework for common requirements. If your team has Angular experience, the patterns will feel familiar.

Limitations

The learning curve is steep. Understanding modules, providers, guards, interceptors, and pipes takes time. The decorator-heavy approach can obscure what's actually happening, making debugging harder. For simple APIs, NestJS adds a lot of ceremony. And despite its microservices support, you still need to configure infrastructure, service discovery, and observability yourself.

When to Consider NestJS

Consider NestJS for large applications with many contributors where consistent architecture matters more than minimal boilerplate. It's particularly suitable for teams with Angular experience or those who value strong conventions across a big codebase.

For a detailed comparison, see our NestJS vs Encore.ts article.

Hono

Hono is a lightweight framework designed for modern JavaScript runtimes. It runs on Cloudflare Workers, Deno, Bun, and Node.js with the same codebase. If you're leaving Fastify because you want something that works at the edge, Hono is purpose-built for that.

The API is clean and feels familiar if you've used Express or Fastify. Middleware is straightforward, and the framework includes validators that work with Zod, Valibot, or its own schema helpers. The tiny bundle size makes it ideal for serverless and edge deployments where cold start time matters. Where Fastify focuses on server-side performance through JSON Schema serialization, Hono optimizes for the constraints of edge runtimes: small bundles, fast cold starts, and minimal memory usage.

import { Hono } from 'hono';
import { zValidator } from '@hono/zod-validator';
import { z } from 'zod';

const app = new Hono();

app.get(
  '/users/:id',
  zValidator('param', z.object({ id: z.string() })),
  async (c) => {
    const { id } = c.req.valid('param');
    const user = await getUserById(id);
    return c.json(user);
  }
);

export default app;

Key Features

• Universal runtime support (Node.js, Deno, Bun, Cloudflare Workers)
• Minimal bundle size for edge deployment
• Built-in middleware for JWT, CORS, logging, and more
• Validator middleware supporting Zod, Valibot, and TypeBox
• First-class TypeScript support

Benefits

Hono excels at edge computing. When deploying to Cloudflare Workers or similar platforms, bundle size directly impacts cold start times and costs. The runtime portability means you can move between platforms without rewriting your application. The API is also simpler than Fastify's, with less ceremony around route definitions.

Limitations

Hono is focused on HTTP routing and middleware. It doesn't provide infrastructure management, service discovery, or built-in observability. For traditional server-side backends with databases and queues, you'll need to configure everything yourself, similar to Express. The ecosystem is growing but still smaller than Fastify's.

When to Consider Hono

Consider Hono when deploying to edge platforms like Cloudflare Workers, when you need cross-runtime compatibility, or when building lightweight APIs where bundle size matters more than infrastructure automation.

For a deeper comparison, see our Hono vs Encore.ts article.

Elysia

Elysia is a TypeScript framework optimized for Bun. If you're exploring Fastify alternatives and your team has adopted Bun as its runtime, Elysia takes advantage of Bun's performance characteristics in ways that other frameworks don't. It uses a TypeBox-based schema system that provides end-to-end type safety from route definitions to response types.

Elysia's approach to validation is closer to Fastify's than other alternatives on this list. You define schemas inline using a builder pattern, and the framework infers TypeScript types from those schemas. This gives you runtime validation and compile-time type checking from a single definition. For Fastify users, this pattern will feel familiar since Fastify also supports TypeBox through its type providers, but Elysia makes it the default rather than an opt-in feature.

import { Elysia, t } from 'elysia';

const app = new Elysia()
  .get('/users/:id', ({ params: { id } }) => {
    return getUserById(id);
  }, {
    params: t.Object({
      id: t.String()
    }),
    response: t.Object({
      id: t.String(),
      name: t.String(),
      email: t.String()
    })
  })
  .listen(3000);

Key Features

• Bun-optimized runtime performance
• End-to-end type safety with TypeBox schemas
• Plugin system with type-safe composition
• Built-in OpenAPI documentation generation
• Eden Treaty for type-safe client generation

Benefits

Elysia's type inference is excellent. The schema definitions produce accurate TypeScript types without manual type annotations, which is a step up from Fastify's JSON Schema approach where type inference requires additional tooling like TypeBox. If you're already using Bun, Elysia's performance optimizations are meaningful.

Limitations

Elysia is tightly coupled to Bun. While it can run on Node.js, you lose the performance benefits that make it attractive. The community is smaller than Fastify's, and the framework is newer, so you may encounter edge cases that aren't well documented. There's no infrastructure management, observability, or service discovery built in.

When to Consider Elysia

Consider Elysia when your team has committed to Bun as its runtime, when you want schema-based validation with better TypeScript inference than Fastify, or when you're building a single-service API and want strong type safety without decorators.

AI Code Generation

TypeScript's backend ecosystem has too many valid ways to structure things. AI coding agents pick a different combination of validation library, database access pattern, and project layout on every prompt. Fastify makes this worse because its JSON Schema definitions are verbose and agents generate inconsistent schemas - sometimes using TypeBox, sometimes raw JSON Schema, sometimes skipping validation entirely.

With Encore, the project's API patterns, infrastructure declarations, and service structure are already defined. An agent reads the existing conventions and follows them. There's one way to define an API, one way to declare a database, and one way to call another service.

Encore also provides an MCP server and editor rules (encore llm-rules init) that give agents access to database schemas, distributed traces, and service architecture. This means agents can generate queries that match your actual tables, debug with real request data, and verify their own work. Read more in How AI Agents Want to Write TypeScript.

How to Choose

Each of these frameworks solves a different set of problems:

Encore.ts is the strongest choice for teams building production backends with multiple services. You get type-safe validation from plain TypeScript types (no JSON Schema), automatic infrastructure provisioning, built-in observability, and a Rust runtime that outperforms Fastify. If the reason you're leaving Fastify is that you want less configuration and more automation, Encore addresses that directly. Its consistent conventions also mean AI coding agents can follow your project's patterns to generate production-ready code.

Express makes sense when you want maximum flexibility and access to the largest middleware ecosystem. It doesn't solve the problems that made you consider leaving Fastify, but it's a known quantity.

NestJS fits teams that want strict architectural conventions and dependency injection. The learning curve is steep, but the consistency pays off in large codebases with many contributors.

Hono is the right choice for edge computing and serverless deployments where bundle size and cold starts are the primary concerns.

Elysia is worth evaluating if your team uses Bun and wants schema-based validation with better TypeScript integration than Fastify offers.

For most teams moving away from Fastify, the pain points are JSON Schema verbosity, infrastructure configuration, and lack of observability. Encore.ts addresses all three while also improving performance. It replaces JSON Schema with standard TypeScript types, provisions infrastructure automatically, and includes distributed tracing out of the box. The best way to evaluate is to build a small project and see how it feels with your team's workflow.

Evaluating your options? Join our Discord community to discuss framework choices with other TypeScript developers.