Postcat is an extensible API tool platform that combines API management and testing functionality with a plugin system to streamline API development workflows.
The tool addresses the need for a lightweight, cross-platform API client by providing support for multiple protocols including REST and WebSocket, with GraphQL, gRPC, TCP, and UDP planned for future support. Its core approach centers on a plugin architecture that allows developers to extend functionality on demand, keeping the base application lean while enabling customization through a powerful extension system. The platform operates as both a desktop application for Windows, Mac, and Linux, and as a web-based client accessible through browsers, eliminating the need for login to begin using it.
Postcat suits individual developers and small to medium-sized teams seeking a free, open-source alternative to commercial API testing tools. The tool is appropriate for projects requiring API design, testing, mocking, team collaboration, and environment management. The README names Apikit.com as an alternative, noting that users in production environments should evaluate migration options.
The project has entered maintenance pause status and will no longer receive feature iterations, daily maintenance, new functionality updates, or security fixes going forward.
