OpenMCP

https://www.open-mcp.org

OpenMCP is both:

1. a standard for converting web APIs into MCP servers
2. an open source registry of servers which follow the standard

Each OpenMCP server gives MCP clients the ability to make requests to a particular web API in a token-efficient way. Together the servers in the registry represent a broad range of services, empowering the underlying client LLMs to fetch data and perform actions on behalf of their users across many domains.

Contents

• Creating a server
• Adding OpenMCP servers to MCP clients
• Converting web API -> OpenMCP

Creating a server

https://www.open-mcp.org/servers/creating-a-server

Adding OpenMCP servers to MCP clients

Remote hosting

...

Local hosting

Local hosting demo - watch video

Requirements:

• Node.js v18 or later (includes npx and npm)

Claude desktop

npx @open-mcp/config add {server-id} \\
  ~/Library/Application\\ Support/Claude/claude_desktop_config.json \\
  --ENV_VAR=abc123

Now restart Claude desktop to load the tools.

Cursor

Run this from the root of your project directory or, to add to all cursor projects, run it from your home directory ~.

npx @open-mcp/config add {server-id} \\
  .cursor/mcp.json \\
  --ENV_VAR=abc123

Now go to Cursor > Settings > Cursor Settings then click MCP to ensure the server is enabled.

Other clients

npx @open-mcp/config add {server-id} \\
  /path/to/config.json \\
  --ENV_VAR=abc123

Alternatives

If you don't want to use the CLI you can use npm to install the package manually, then add a node command to your client config with an absolute path to dist/index.js. See the individual server READMEs for more details.

Converting web API -> OpenMCP

REST openapi.yaml / openapi.json

...

gRPC service.proto

...

JSON-RPC openrpc.json

...

GraphQL schema.gql

...

SOAP service.wsdl

...

PostgREST schema.sql

...