bbonnin/openapi-to-mcp

Overview

OpenApiMCPServer is a Java-based MCP server that automatically converts any OpenAPI or Swagger specification into a set of usable MCP tools. It reads the API spec and exposes each endpoint as a tool that can be invoked through the MCP protocol.

Best for

Best for
Developers who need to quickly expose existing REST APIs as MCP tools without writing custom adapters

Use cases

• Expose a REST API as MCP tools for use in AI agents
• Quickly prototype MCP integrations from existing OpenAPI specs
• Bridge legacy Swagger-defined APIs into modern MCP workflows

How to use

Install

java -jar $PATH_TO_JAR/openapi-mcp-server.jar --openapi.location=<swagger file or URL>

Notes

OpenApiMCPServer is a Java-based MCP server that automatically converts any OpenAPI or Swagger specification into a set of usable MCP tools. It reads the API spec and exposes each endpoint as a tool that can be invoked through the MCP protocol.

5 stars on GitHub. Last updated 2025-12-05. Licensed MIT.

Use cases

• Expose a REST API as MCP tools for use in AI agents
• Quickly prototype MCP integrations from existing OpenAPI specs
• Bridge legacy Swagger-defined APIs into modern MCP workflows

Pros

• Zero manual tool definition needed for any valid OpenAPI spec
• Lightweight Java implementation with minimal dependencies
• Works with both OpenAPI 2.0 (Swagger) and 3.0 specs

Cons

• Requires Java runtime, limiting deployment options for non-Java stacks
• No built-in authentication or rate limiting for the generated tools
• Limited to read-only conversion; does not handle complex API workflows

Indexed from awesome-mcp-servers-punkpeye and enriched against its public facts.