Pretender

Pretender is a mock server library for XMLHttpRequest and Fetch in the browser, providing an express/sinatra-style DSL for defining routes and handlers. Current stable version is 3.4.7, released with regular updates. It works by temporarily replacing native XMLHttpRequest and Fetch to intercept all requests. Key differentiators: minimal setup, supports dynamic route segments, timing simulation, and multiple map registration. Note: Only works in browsers, not Node.js.