VercelDeployer

The VercelDeployer bundles your Mastra server and generates output conforming to Vercel's Build Output API. Vercel deploys this output directly as serverless functions.

Installation

To use VercelDeployer, install the @mastra/deployer-vercel package:

npm

npm install @mastra/deployer-vercel@latest

pnpm

pnpm add @mastra/deployer-vercel@latest

Yarn

yarn add @mastra/deployer-vercel@latest

Bun

bun add @mastra/deployer-vercel@latest

Usage example

Import VercelDeployer and set it as the deployer in your Mastra configuration:

src/mastra/index.ts

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

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

Constructor options

The deployer accepts overrides that are written to the Vercel Output API function config (.vc-config.json):

• maxDuration?: number — Function execution timeout (in seconds)
• memory?: number — Function memory (in MB)
• regions?: string[] — Regions to deploy the function (e.g. ['sfo1','iad1'])

These options are merged into .vercel/output/functions/index.func/.vc-config.json while preserving default fields (handler, launcherType, runtime, shouldAddHelpers).

Example with overrides

src/mastra/index.ts

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

export const mastra = new Mastra({
  deployer: new VercelDeployer({
    maxDuration: 600,
    memory: 1536,
    regions: ["sfo1", "iad1"],
  }),
});

Build output

After running mastra build, the deployer generates a .vercel/output directory conforming to Vercel's Build Output API (v3). This directory contains routing configuration and serverless function bundles that Vercel deploys directly, bypassing framework detection.

The output contains:

• config.json — Routing configuration that directs all requests to your function
• functions/ — Your Mastra server bundled as a serverless function

.vercel/
└── output/
    ├── config.json
    └── functions/
        └── index.func/
            ├── .vc-config.json
            ├── index.mjs
            └── node_modules/

This folder is generated during build and should not be committed to version control.