Run an MCP Server on Vercel

Usage

Update api/server.js with your tools, prompts, and resources following the MCP TypeScript SDK documentation.

There is also a Next.js version of this template

MCP Client Integration

When adding this server to an MCP client application, use your deployment URL followed by /mcp (Streamable HTTP). The SSE transport is available at /sse:

https://your-deployment-url.vercel.app/mcp

MCP Apps UI hook

This template registers an MCP Apps UI resource at ui://hello_app_panel and links it to the hello_world tool via _meta.ui.resourceUri. MCP hosts that support MCP Apps will render the panel inline and forward tool calls initiated from the UI.

Example Tools

The template includes one example tool to get you started:

• hello_world - Returns a hello message with an allowlisted style input.

Notes for running on Vercel

• Make sure you have Fluid compute enabled for efficient execution
• After enabling Fluid compute, open vercel.json and adjust max duration to 800 if you using a Vercel Pro or Enterprise account
• Deploy the MCP template

Local dev

• Run vercel dev for local development
• Alternatively, integrate the system into the server framework of your choice.

Testing & validation

You can list tools via the included clients:

node scripts/test-streamable-http-client.mjs http://localhost:3000

Or for SSE transport:

node scripts/test-client.mjs http://localhost:3000

To manually call the tool via Streamable HTTP, use a simple JSON-RPC request (replace the origin as needed):

curl -sS http://localhost:3000/mcp \\
  -H 'content-type: application/json' \\
  -d '{\"jsonrpc\":\"2.0\",\"id\":1,\"method\":\"tools/call\",\"params\":{\"name\":\"hello_world\",\"arguments\":{\"style\":\"friendly\"}}}'

Sample Client

scripts/test-client.mjs contains a sample client to try invocations.

node scripts/test-client.mjs https://mcp-on-vercel.vercel.app