tiger

Tiger is a free, open source desktop application for testing APIs. An API is a connection point that lets different pieces of software talk to each other. Developers use tools like this to send test requests to those connection points and see what comes back, before writing code that depends on those responses.

What sets Tiger apart from older tools like Postman is how it saves your work. Every request you create becomes a plain text file on your own computer, using a simple format called .tiger. Because the files are plain text, you can put them into Git, the version-control system most developers already use for code. That means you can track changes, roll back mistakes, and review API changes in the same pull requests where you review code. No account is required, and nothing leaves your machine unless you choose to share it.

Tiger runs as a desktop app on macOS and Windows. It supports REST, GraphQL, and XML-based APIs. You can define sets of variables for different environments (such as development versus production), chain requests together so the result of one feeds into the next call, and run an entire collection of requests in order to check they all succeed. A performance mode fires many requests simultaneously and reports timing numbers including average and worst-case response times.

One thing Tiger offers that most similar tools do not is a built-in MCP server. MCP is a protocol that lets AI coding assistants such as Claude or Cursor control external tools. Once you configure Tiger's MCP server, an AI assistant can list your saved requests, inspect their contents, and actually send them on your behalf, without you leaving the chat window. This is the main feature the project emphasizes over its closest open source competitors.

Tiger is MIT licensed, at version 0.3.1, and maintained by a single developer.