mitmproxy : mitmproxy is your swiss-army knife for debugging, testing, privacy measurements, and penetration testing. It can be used to intercept, inspect, modify...
Vcr : Record your test suite's HTTP interactions and replay them during future test runs for fast, deterministic, accurate tests.
Mock Service Worker : Mock by intercepting requests on the network level. Seamlessly reuse the same mock definition for testing, development, and debugging.
httpbin.org : A simple HTTP Request & Response Service.
Security Headers : I built securityheaders.io after deploying security headers like CSP and HSTS to my own site. I wanted a quick and easy way to check if other sites we...
toxy is a fully programmatic and hackable HTTP proxy to simulate server failure scenarios and unexpected network conditions, built for node.js/io.js.