Postcatlab/postcat

Health v2 · maintenance only

Adoption not part of the score

5542 stars · 798 forks observed · 2026-08-28

What it is AI-extracted, prompt v1, taxonomy v1, 2026-08-29, confidence not recorded

Postcat is an open-source, cross-platform API development and testing tool supporting REST and WebSocket protocols, with API design, documentation, mock, and team collaboration features. It has a plugin system for extensibility, but the project is now officially discontinued and unmaintained.

Use cases

• test REST APIs with a GUI client
• design and document APIs
• mock API responses during development
• manage WebSocket connections
• extend an API client with custom plugins
• share API docs with a team
• find a free Postman alternative

When to choose

• you need a free, lightweight GUI API client for REST or WebSocket
• you want an extensible API tool with a plugin system
• you're okay using software without future updates or security fixes

When to avoid

• you need actively maintained software with security patches
• you need GraphQL, gRPC, or other protocols beyond REST/WebSocket
• you rely on long-term vendor support for production tooling

Facets

application · maturity abandoned

http-client developer-tools mock-api api-framework plugin-system developer-tools apis web-development testing cross-platform windows browser api-client api-testing api-documentation postman-alternative rest-client websocket-client extensible discontinued electron macos linux web-server

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For agents

markdown · JSON · MCP: product_card(name="Postcatlab/postcat")