A multithreaded hyperlink checker that crawls a site and looks for 404s. Unfortunately, not maintained anymore and written in Python2. Still useful.
A plugin for shaarli to remove or tag broken links. Check out into the plugins/ subdirectory, go to the plugins control panel, and enable it. After you've done that you need to tell the plugin to run by scrolling all the way to the bottom and entering REMOVE or TAG. Then it will execute. This script will time out on shared hosting.
Mypy is an optional static type checker for Python. You can add type hints to your Python programs, and use mypy to type check them statically. Find bugs in your programs without even running them! You can mix dynamic and static typing in your programs. You can always fall back to dynamic typing when static typing is not convenient, such as for legacy code.
Can be loaded as a module or used as a command-line tool for manual checking. Can be integrated with text editors or IDEs to operate automatically.
Secure your email server with STARTTLS Everywhere! Your email service can be insecure in numerous different ways. The service below performs a quick check of your email server's security configuration, including whether STARTTLS is supported, and whether it may qualify for the STARTTLS Policy List.
A website that tests to see if arbitrary URLs are accessible from within China (behind Golden Shield/The Great Firewall).