Postcat is a free, open-source API development and testing application designed for developers and software teams. It provides a unified interface for creating, organizing, documenting, and testing application programming interfaces. The software supports HTTP REST and WebSocket protocols for communicating with backend services. Users can configure requests, inspect responses, and manage API environments and global variables. Its extensible plugin system allows additional tools and functionality to be incorporated into development workflows. Postcat also provides API design, documentation, collaboration, and sharing capabilities. Available for Windows, macOS, Linux, and web browsers, the project has entered maintenance suspension and no longer receives regular feature updates or security fixes.

Features

  • HTTP REST and WebSocket API testing
  • API request organization and response inspection
  • API documentation and interface design tools
  • Environment configuration and global variables
  • Extensible plugin architecture and customizable themes
  • Cross-platform desktop and browser-based interfaces

Project Samples

Postcat Screenshot 1

Project Activity

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Categories

Software Testing, API Clients

License

Apache License V2.0

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Additional Project Details

Operating Systems

Linux, Mac, Windows

Programming Language

JavaScript

Related Categories

JavaScript Software Testing Tool, JavaScript API Clients

Registered

2026-11-02
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