---
title: Fastify on Vercel
product: vercel
url: /docs/frameworks/backend/fastify
type: how-to
prerequisites:
  - /docs/frameworks/backend
  - /docs/frameworks
related:
  - /docs/functions
  - /docs/fluid-compute
  - /docs/deployments/environments
  - /docs/instant-rollback
  - /docs/vercel-firewall
summary: Deploy Fastify applications to Vercel with zero configuration.
install_vercel_plugin: npx plugins add vercel/vercel-plugin
---

# Fastify on Vercel

Fastify is a web framework highly focused on providing the best developer experience with the least overhead and a powerful plugin architecture. You can deploy a Fastify app to Vercel with zero configuration using [Vercel Functions](/docs/functions).

Fastify applications on Vercel benefit from:

- [Fluid compute](/docs/fluid-compute): Pay for the CPU you use, automatic cold start reduction, optimized concurrency, background processing, and more
- [Preview deployments](/docs/deployments/environments#preview-environment-pre-production): Test your changes in a copy of your production infrastructure
- [Instant Rollback](/docs/instant-rollback): Recover from breaking changes or bugs in milliseconds
- [Vercel Firewall](/docs/vercel-firewall): Protect your applications from a wide range of threats with a robust, multi-layered security system
- [Secure Compute](/docs/secure-compute): Create private links between your Vercel-hosted backend and other clouds

## Get started with Fastify on Vercel

You can quickly deploy a Fastify application to Vercel by creating a Fastify app or using an existing one:

## Fastify entrypoint detection

To allow Vercel to deploy your Fastify application and process web requests, your server entrypoint file should be named one of the following:

- `src/app.{js,mjs,cjs,ts,cts,mts}`
- `src/index.{js,mjs,cjs,ts,cts,mts}`
- `src/server.{js,mjs,cjs,ts,cts,mts}`
- `app.{js,mjs,cjs,ts,cts,mts}`
- `index.{js,mjs,cjs,ts,cts,mts}`
- `server.{js,mjs,cjs,ts,cts,mts}`

For example, use the following code as an entrypoint:

```js filename="src/index.ts"
import Fastify from 'fastify';

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

fastify.get('/', async (request, reply) => {
  return { hello: 'world' };
});

fastify.listen({ port: 3000 });
```

### Local development

Use `vercel dev` to run your application locally

```bash filename="terminal"
vercel dev
```

> **💡 Note:** Minimum CLI version required: 48.6.0

### Deploying the application

To deploy, [connect your Git repository](/new) or [use Vercel CLI](/docs/cli/deploy):

```bash filename="terminal"
vc deploy
```

> **💡 Note:** Minimum CLI version required: 48.6.0

## Vercel Functions

When you deploy a Fastify app to Vercel, your Fastify application becomes a single [Vercel Function](/docs/functions) and uses [Fluid compute](/docs/fluid-compute) by default. This means your Fastify app will automatically scale up and down based on traffic.

## Limitations

All [Vercel Functions limitations](/docs/functions/limitations) apply to the Fastify application, including the size of the application being limited to 250MB.

## More resources

Learn more about deploying Fastify projects on Vercel with the following resources:

- [Fastify official documentation](https://fastify.dev/docs/latest/)
- [Vercel Functions documentation](/docs/functions)
- [Backend templates on Vercel](https://vercel.com/templates?type=backend)


---

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