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0mcp sits between an MCP client and your API. It hosts the MCP server, translates tool calls into standard HTTP requests, forwards them to your API, and returns the response to the client. Your API remains unchanged. 0mcp simply provides an MCP-compatible interface on top of it.
0mcp translates and forwards requests. Your API still owns its business logic, data, authentication, and authorization decisions.

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Request flow

When an AI client calls a tool, the request follows this path: 
MCP Client
     │
     ▼
Hosted 0mcp Server
     │
Translate Tool → HTTP Request
     │
     ▼
Your API
     │
HTTP Response
     │
     ▼
Hosted 0mcp Server
     │
     ▼
MCP Client
0mcp is responsible for translating between the MCP protocol and your existing REST API, allowing any compatible AI client to use your API without requiring changes to your backend.

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Authentication

Authentication stays with your API. When a tool requires authentication, the MCP client provides the necessary credentials, such as a Bearer token or API key, when invoking the tool. 0mcp securely forwards those credentials to your upstream API as part of the HTTP request. Your API authenticates the request exactly as it would for any other client. This means:
  • No changes to your existing authentication system
  • No shared API secrets stored in 0mcp
  • Your API remains the source of truth for authorization
Read the authentication model for supported credential patterns and safe setup guidance.