REST API MCP Server

A dynamic Model Context Protocol (MCP) server that automatically discovers and generates tools from any REST API using OpenAPI/Swagger specifications. Point it at any OpenAPI spec and it instantly exposes every endpoint as an MCP tool — zero manual configuration.

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Documentation

For full documentation, guides, and examples, visit:

https://nife.io/mcp_opensource

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Installation

pip install nife-restapi-mcp-server

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Configuration

There are four ways to configure the server. They are applied in priority order — higher entries win:

Priority	Method	Best for
1	CLI arguments	One-off runs, testing
2	Environment variables	Docker, CI/CD, shell scripts
3	.env file	Local development
4	Defaults	Nothing required by default

Method 1 — CLI Arguments

restapi-mcp-server --base-url https://api.example.com --spec-url https://api.example.com/openapi.json --token mytoken

All available flags:

--base-url URL       REST API base URL (required if not set via env)
--spec-url URL       OpenAPI/Swagger spec URL or local file path (required if not set via env)
--token TOKEN        API access token for bearer authentication
--auth-type TYPE     Authentication type: bearer, apikey, basic, none (default: bearer)
--mode stdio|http    Server mode (default: stdio)
--port PORT          HTTP port, only used in http mode (default: 8080)
--host HOST          HTTP host, only used in http mode (default: 0.0.0.0)
--log-level LEVEL    Logging level: DEBUG, INFO, WARNING, ERROR (default: INFO)
--env-file PATH      Path to a custom .env file
--version            Show version and exit

Method 2 — Environment Variables

export REST_API_BASE_URL=https://api.example.com
export OPENAPI_SPEC_URL=https://api.example.com/openapi.json
export API_ACCESS_TOKEN=your_token_here
export MCP_MODE=stdio

restapi-mcp-server

Method 3 — .env File

Create a .env file in your working directory:

REST_API_BASE_URL=https://api.example.com
OPENAPI_SPEC_URL=https://api.example.com/openapi.json
API_ACCESS_TOKEN=your_token_here
AUTH_TYPE=bearer
MCP_MODE=stdio
LOG_LEVEL=INFO

Then just run:

restapi-mcp-server

Method 4 — Claude Desktop Config (most common for MCP use)

No .env file needed. Pass everything via the env block in claude_desktop_config.json:

{
  "mcpServers": {
    "restapi": {
      "command": "restapi-mcp-server",
      "env": {
        "REST_API_BASE_URL": "https://api.example.com",
        "OPENAPI_SPEC_URL": "https://api.example.com/openapi.json",
        "API_ACCESS_TOKEN": "your_token_here",
        "MCP_MODE": "stdio",
        "ENABLE_HTTP_ENDPOINT": "false"
      }
    }
  }
}

Claude Desktop injects the env block values directly into the process — this is the standard MCP pattern.

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Environment Variable Reference

Variable	Required	Default	Description
REST_API_BASE_URL	Yes	—	REST API base URL
OPENAPI_SPEC_URL	Yes	—	OpenAPI/Swagger spec URL or local file path
AUTH_TYPE	No	bearer	Auth method: bearer, apikey, basic, none
API_ACCESS_TOKEN	No	—	Bearer token for auth
API_KEY_HEADER	No	X-API-Key	Header name for API key auth
API_KEY_VALUE	No	—	API key value
BASIC_AUTH_USERNAME	No	—	Username for basic auth
BASIC_AUTH_PASSWORD	No	—	Password for basic auth
MCP_MODE	No	stdio	stdio or http
ENABLE_HTTP_ENDPOINT	No	true	Enable HTTP health/metrics endpoints
MCP_SERVER_PORT	No	8080	HTTP server port
MCP_SERVER_HOST	No	0.0.0.0	HTTP server host
LOG_LEVEL	No	INFO	Logging verbosity
REQUEST_TIMEOUT	No	30	Request timeout in seconds
SCHEMA_CACHE_TTL	No	3600	Schema cache TTL in seconds

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Operating Modes

MCP Mode (stdio) — for Claude Desktop, Cursor, MCP clients

restapi-mcp-server --base-url https://api.example.com --spec-url https://api.example.com/openapi.json --mode stdio

Communicates via stdin/stdout. No HTTP server is started. This is the default.

HTTP Mode — for Docker, Kubernetes, server deployments

restapi-mcp-server --base-url https://api.example.com --spec-url https://api.example.com/openapi.json --mode http --port 8080

Starts an HTTP server with health and metrics endpoints:

• GET / — server info
• GET /health — health check
• GET /metrics — server metrics
• GET /schema — OpenAPI schema summary
• GET /tools — all generated tools
• GET /api/endpoints — all API endpoints

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Authentication Methods

Bearer Token

AUTH_TYPE=bearer
API_ACCESS_TOKEN=your_token

API Key

AUTH_TYPE=apikey
API_KEY_HEADER=X-API-Key
API_KEY_VALUE=your_key

Basic Authentication

AUTH_TYPE=basic
BASIC_AUTH_USERNAME=username
BASIC_AUTH_PASSWORD=password

No Authentication

AUTH_TYPE=none

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Docker

docker build -t restapi-mcp-server .

docker run -p 8080:8080 \
  -e REST_API_BASE_URL=https://api.example.com \
  -e OPENAPI_SPEC_URL=https://api.example.com/openapi.json \
  -e API_ACCESS_TOKEN=your_token \
  -e MCP_MODE=http \
  restapi-mcp-server

Or with Docker Compose:

cp .env.example .env   # fill in your values
docker-compose up

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Available Tools

The server dynamically generates the following tool types:

Endpoint Tools

Named by HTTP method and path: <method>_<path_parts>

Examples:

• get_users
• post_users
• get_users_by_id
• delete_users_by_id
• put_users_by_id

Utility Tools

• list_available_endpoints — list all endpoints (filterable by method or path)
• get_endpoint_info — detailed info about a specific endpoint
• get_schema_info — OpenAPI schema summary or specific model details
• execute_custom_request — run any HTTP request with full control
• health_check — server health and schema status

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OpenAPI Specification Support

• OpenAPI 3.x (full support)
• Swagger 2.0 (backward compatible)

Supported spec sources:

• Remote JSON URL
• Remote YAML URL
• Local JSON file
• Local YAML file

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Key Features

• Zero config endpoints — auto-parses any OpenAPI/Swagger spec and generates MCP tools
• Dual mode — stdio for MCP clients, HTTP for server deployments
• Flexible config — CLI args, env vars, .env file, or Claude Desktop env block
• Multiple auth methods — Bearer, API key, Basic, or none
• Production ready — Docker, Kubernetes, AWS ECS, Google Cloud Run compatible
• Self-documenting — list_available_endpoints, get_endpoint_info, get_schema_info tools built in
• Documentation — https://nife.io/mcp_opensource

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Troubleshooting

[ERROR] REST API base URL not configured

Set REST_API_BASE_URL via any method above. The most common fix:

restapi-mcp-server --base-url https://your-api.com

[ERROR] OpenAPI spec URL not configured

Set OPENAPI_SPEC_URL via any method above:

restapi-mcp-server --spec-url https://your-api.com/openapi.json

Port already in use

Change the port:

restapi-mcp-server --mode http --port 9090

Docker container exits immediately

Make sure you're using HTTP mode:

docker run -e MCP_MODE=http -e REST_API_BASE_URL=... -e OPENAPI_SPEC_URL=... restapi-mcp-server

Schema not loading

• Verify the spec URL is reachable
• Check the format is valid JSON or YAML
• Ensure the spec is OpenAPI 3.x or Swagger 2.0

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License

MIT