Postmancer MCP Server

What is Postmancer?

Postmancer is a standalone MCP server for API testing and management, allowing AI assistants like Claude to make HTTP requests, manage collections of API endpoints, and test API responses through natural language. It offers similar functionality to tools like Postman or Insomnia but is designed specifically for AI assistants.

How to use Postmancer?

Install globally with npm install -g postmancer or run directly with npx postmancer. For Claude Desktop, add a configuration entry with "command": "npx", "args": ["-y", "postmancer"] to the MCP server list. Alternatively, run with Docker using docker run -i --rm --mount type=bind,src=/path/to/collections,dst=/data/collections postmancer.

Key features of Postmancer

• Make HTTP requests to any REST API
• Save and organize requests in collections
• Set and use environment variables with variable substitution
• Multiple authentication methods (Basic, Bearer, API Key, OAuth2)
• Request/response history and testing

Use cases of Postmancer

• AI assistant testing and debugging REST APIs via natural language
• Managing a collection of reusable API endpoints
• Running saved requests with environment variable substitution
• Using different authentication methods for API testing
• Maintaining request/response history for auditing or debugging