# Deploy a Bun application on Vercel (/docs/guides/deployment/vercel)

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Related: [Deploy a Bun application on Railway](/docs/guides/deployment/railway.md), [Deploy a Bun application on Render](/docs/guides/deployment/render.md), [Deploy a Bun application on AWS Lambda](/docs/guides/deployment/aws-lambda.md), [Deploy a Bun application on DigitalOcean](/docs/guides/deployment/digital-ocean.md), [Deploy a Bun application on Google Cloud Run](/docs/guides/deployment/google-cloud-run.md), [Delete a file](/docs/guides/write-file/unlink.md)

[Vercel](https://vercel.com/) is a cloud platform for building, deploying, and scaling apps.

<Warning>
  The Bun runtime is in Beta. Some features are not yet supported — for example, automatic source maps, byte-code
  caching, and metrics on `node:http/https`.
</Warning>

<Note>
  `Bun.serve` is not supported on Vercel Functions. Use Bun with frameworks supported by Vercel, like Next.js, Express,
  Hono, or Nitro.
</Note>

***

<Steps>
  <Step title="Configure Bun in vercel.json">
    To enable the Bun runtime for your Functions, add a `bunVersion` field in your `vercel.json` file:

    ```json vercel.json icon="file-json"
    {
    	"bunVersion": "1.x" // [!code ++]
    }
    ```

    Vercel automatically detects this configuration and runs your application on Bun. The value must be `"1.x"`; Vercel handles the minor version internally.

    For best results, match your local Bun version with the version used by Vercel.
  </Step>

  <Step title="Next.js configuration">
    If you’re deploying a **Next.js** project (including ISR), update your `package.json` scripts to use the Bun runtime:

    ```json package.json icon="file-json"
    {
    	"scripts": {
    		"dev": "bun --bun next dev", // [!code ++]
    		"build": "bun --bun next build" // [!code ++]
    	}
    }
    ```

    <Note>
      The `--bun` flag runs the Next.js CLI under Bun. Bundling (with Turbopack or Webpack) is unchanged.
    </Note>

    With these scripts, both local development and builds use Bun.
  </Step>

  <Step title="Deploy your app">
    Connect your repository to Vercel, or deploy from the CLI:

    ```bash terminal icon="terminal"
    # Using bunx (no global install)
    bunx vercel login
    bunx vercel deploy
    ```

    Or install the Vercel CLI globally:

    ```bash terminal icon="terminal"
    bun i -g vercel
    vercel login
    vercel deploy
    ```

    [Learn more in the Vercel Deploy CLI documentation →](https://vercel.com/docs/cli/deploy)
  </Step>

  <Step title="Verify the runtime">
    To confirm your deployment uses Bun, log the Bun version:

    ```ts index.ts icon="/icons/typescript.svg"
    console.log("runtime", process.versions.bun);
    ```

    ```txt
    runtime 1.3.3
    ```

    [See the Vercel Bun Runtime documentation for feature support →](https://vercel.com/docs/functions/runtimes/bun#feature-support)
  </Step>
</Steps>

***

* [Fluid compute](https://vercel.com/docs/fluid-compute): Both Bun and Node.js runtimes run on Fluid compute and support the same core Vercel Functions features.
* [Middleware](https://vercel.com/docs/routing-middleware): To run Routing Middleware with Bun, set the runtime to `nodejs`:

```ts middleware.ts icon="/icons/typescript.svg"
export const config = { runtime: "nodejs" }; // [!code ++]
```