Fastify vs NestJS
Which should you use? A side-by-side look at what each one does, who it suits, what it costs, how hard it is to set up, and where each falls short.
Open source · MIT
A fast, low-overhead web framework for building servers and APIs with Node.js.
Open source · MIT
A TypeScript/JavaScript framework for building structured server-side Node.js applications.
The short answer
Choose Fastify if you need…
- Node.js developers building JSON APIs or backend services
- Teams that care about request throughput and want a lightweight framework
- Projects that want schema-based validation of routes and responses
- Developers who want to organize code into reusable plugins
Choose NestJS if you need…
- Teams building larger back-end APIs in TypeScript who want enforced structure
- Developers coming from Angular-style or dependency-injection-based frameworks
- Projects that may later need microservices or WebSocket support, based on the repository topics
Side-by-side
| Fastify | NestJS | |
|---|---|---|
| Type | Library | Framework |
| Price | Free and open source | Free and open source |
| Licence | MIT | MIT |
| GitHub stars | 37.3k | 77k |
| Setup difficulty | Beginner | Intermediate |
| How you get it | Install with a package manager | See the README |
| Main language | JavaScript | TypeScript |
| Last code update | 4 days ago | 4 days ago |
What each one is
Fastify
Fastify is a framework for building web servers and APIs in Node.js. You define routes, such as a URL that returns data, and Fastify handles incoming requests with minimal extra work per request. It also offers a plugin system, input and output validation using JSON Schema, and built-in logging through Pino.
NestJS
Nest is a framework for building server-side applications with Node.js, written for TypeScript and usable with JavaScript. It organizes code into modules, controllers, and services so larger back-end projects stay consistent as they grow. According to its description, it is meant for efficient, scalable, enterprise-grade server apps; the README provided here was empty, so specifics beyond that are not verified.
Best for
Fastify
- Node.js developers building JSON APIs or backend services
- Teams that care about request throughput and want a lightweight framework
- Projects that want schema-based validation of routes and responses
- Developers who want to organize code into reusable plugins
NestJS
- Teams building larger back-end APIs in TypeScript who want enforced structure
- Developers coming from Angular-style or dependency-injection-based frameworks
- Projects that may later need microservices or WebSocket support, based on the repository topics
Strengths
Fastify
- The README reports high request throughput in a synthetic hello-world benchmark, with the caveat that real results depend on the application
- Supports JSON Schema validation and serialization for routes
- Includes a plugin architecture and hooks for extending behavior
NestJS
- Large, active open-source project with a MIT license and about 77k GitHub stars
- Written in TypeScript, which helps catch errors before runtime
- Has a recent release (v12.3.0) and a recent last push date
Not ideal for
Fastify
- Beginners who have not yet learned Node.js basics, since the framework assumes JavaScript familiarity
- Projects that need a non-Node.js language, because Fastify is for Node.js only
- Teams expecting a large built-in feature set; much functionality comes from plugins, per the docs
NestJS
- Very small scripts or single-endpoint services, where a framework adds more structure than needed
- People who want a minimal, unopinionated library; Nest is opinionated about how code is organized
- Anyone needing details on specific features here, since the README supplied was empty and could not be checked
Trade-offs
Fastify
- Benchmark figures come from the maintainers' own synthetic test and may not match your workload
- The README's benchmark table lists an older Fastify version (4.0.0), so the numbers are not current
- Binding to 0.0.0.0 in containers requires care, since the README warns of security risks
NestJS
- The README was not available in the supplied material, so feature details could not be verified here
- Opinionated structure may feel heavy for small projects
- Requires familiarity with Node.js and TypeScript concepts such as decorators and dependency injection
Getting started
Fastify
Install Fastify in an existing project
npm i fastifyGenerate a new Fastify project
npm init fastifyNestJS
Clone the repository
git clone https://github.com/nestjs/nestFrequently asked questions
What is the difference between Fastify and NestJS?
Fastify: A fast, low-overhead web framework for building servers and APIs with Node.js. NestJS: A TypeScript/JavaScript framework for building structured server-side Node.js applications. Fastify suits node.js developers building json apis or backend services, while NestJS suits teams building larger back-end apis in typescript who want enforced structure.
Are Fastify and NestJS free?
Fastify: Free and open source. NestJS: Free and open source.
Which is easier to set up, Fastify or NestJS?
Fastify is easier to get started with (rated beginner); NestJS is rated intermediate and usually needs more setup.
Is Fastify or NestJS more popular?
NestJS has more GitHub stars (77k) than Fastify (37.3k). Popularity isn't the same as fit — check which one matches your use case above.
What are other alternatives to Fastify and NestJS?
Other options people compare them with include Express, Koa, refine.
Keep comparing
Built from our catalogue entries for both products: open-source details come from each project's README (AI-assisted, refreshed weekly) and GitHub data; AI-tool details are editorial. Spotted something wrong? Let us know from either product's page.