HTTPolice is a validator or “linter” for HTTP requests and responses. It can spot bad header syntax, inappropriate status codes, and other potential problems in your HTTP server or client.
See example report.
As a command-line tool, it can read HAR files or raw HTTP/1.x TCP streams. It can integrate with mitmproxy for TLS-encrypted and HTTP/2 traffic. Or you can use it as a Python (3.4+) library. There is a Django integration package and a third-party Chrome extension.
Start with the quickstart.
A full user manual is available. Also, a list of all problems HTTPolice can detect.
HTTPolice was partly inspired by REDbot, another QA tool for the Web. But the approach is different: instead of actively testing your server, HTTPolice just analyzes anything you feed into it. Thus, it can be used on requests and responses captured from a real process or test suite.
HTTPolice is hosted on GitHub and released under the MIT license (see LICENSE.txt). If you want to hack on HTTPolice, check out HACKING.rst.
BrowserStack kindly provide a free subscription for testing HTTPolice.