OpenMCP
OpenMCP is both:
- a standard for converting web APIs into MCP servers
- 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
https://www.open-mcp.org/servers/creating-a-server
Adding OpenMCP servers to MCP clients
Remote hosting
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Local hosting
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
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gRPC service.proto
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JSON-RPC openrpc.json
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GraphQL schema.gql
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SOAP service.wsdl
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PostgREST schema.sql
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