# Deploy Mastra to Vercel

Use `@mastra/deployer-vercel` to deploy your Mastra server as serverless functions on Vercel. The deployer bundles your code and generates a `.vercel/output` directory conforming to Vercel's [Build Output API](https://vercel.com/docs/build-output-api/v3), ready to deploy with no additional configuration.

> **Info:** If you're using a [server adapter](https://mastra.ai/docs/server/server-adapters) or [web framework](https://mastra.ai/docs/deployment/web-framework), deploy the way you normally would for that framework.

## Before you begin

You'll need a [Mastra application](https://mastra.ai/guides/getting-started/quickstart) and a [Vercel](https://vercel.com/) account.

Vercel Functions use an ephemeral filesystem, so any storage you configure (including observability storage) must be hosted externally. If you're using [LibSQLStore](https://mastra.ai/reference/storage/libsql) with a file URL, switch to a remotely hosted database.

## Installation

Add the `@mastra/deployer-vercel` package to your project:

**npm**:

```bash
npm install @mastra/deployer-vercel@latest
```

**pnpm**:

```bash
pnpm add @mastra/deployer-vercel@latest
```

**Yarn**:

```bash
yarn add @mastra/deployer-vercel@latest
```

**Bun**:

```bash
bun add @mastra/deployer-vercel@latest
```

Import [`VercelDeployer`](https://mastra.ai/reference/deployer/vercel) and set it as the deployer in your Mastra configuration:

```typescript
import { Mastra } from "@mastra/core";
import { VercelDeployer } from "@mastra/deployer-vercel";

export const mastra = new Mastra({
  deployer: new VercelDeployer(),
});
```

## Usage

1. Push your project to a remote Git provider (e.g. GitHub) and connect your repository to Vercel.

   By default, Vercel runs `npm run build`, which triggers `mastra build`. If you don't have a build script, add `"build": "mastra build"` to your `package.json`.

   > **Note:** Remember to set your environment variables needed to run your application (e.g. your [model provider](https://mastra.ai/models/providers) API key).

2. Once you're ready, click **Deploy** and wait for the first deployment to complete.

3. Verify your deployment at `https://<your-project>.vercel.app/api/agents`, which should return a JSON list of your agents.

   Since the Mastra server prefixes every endpoint with `/api`, you have to add it to your URLs when making requests.

4. You can now call your Mastra endpoints over HTTP.

   > **Note:** Set up [authentication](https://mastra.ai/docs/server/auth) before exposing your endpoints publicly.

## Optional overrides

The Vercel deployer supports configuration options that are written to the Vercel Output API function config. See the [`VercelDeployer` reference](https://mastra.ai/reference/deployer/vercel) for available options like `maxDuration`, `memory`, and `regions`.

## Observability

Serverless functions can terminate immediately after returning a response. Any pending async work - like sending telemetry - may get killed before completing. Awaiting `flush()` ensures all traces are sent before the function exits.

```typescript
import type { VercelRequest, VercelResponse } from "@vercel/node";
import { mastra } from "../src/mastra";

export default async function handler(req: VercelRequest, res: VercelResponse) {
  const { message } = req.body;
  const agent = mastra.getAgent("myAgent");
  const result = await agent.generate([{ role: "user", content: message }]);

  const observability = mastra.getObservability();
  await observability?.flush();

  return res.json(result);
}
```

> **Warning:** The Vercel deployer doesn't include `flush` calls. If you need this, you'll need to wrap the handler yourself to add the logic before returning the response. Alternatively, deploy to a long-running server like a [virtual machine](https://mastra.ai/guides/deployment/digital-ocean) where this isn't an issue.

## Related

- [VercelDeployer reference](https://mastra.ai/reference/deployer/vercel)
- [Deployment overview](https://mastra.ai/docs/deployment/overview)
- [Server adapters](https://mastra.ai/docs/server/server-adapters)
- [Web framework integration](https://mastra.ai/docs/deployment/web-framework)