If you've ever hit an error like port 3000 already in use, you know the drill: hunt through Task Manager, guess which process is the culprit, and hope killing the right thing doesn't break something else. PortKiller does that hunting for you. It watches which programs are listening on network ports, shows them in a searchable list, and lets you stop them politely first, with a forced stop as a fallback.
It comes in two forms. A small app sits in your system tray, quietly refreshing so you can spot and free a busy port in a couple of clicks. For everything else there's a command line tool: list what's listening, search by name or port, and kill a blocker without leaving your terminal. Both speak the same language, and the command line tool can output structured results, so it slots neatly into scripts.
Small conveniences round it out. You can mark favorite ports for quick access, have it start with Windows, and tweak settings to match how you like to work. It's a focused tool for a common, everyday annoyance, built to get out of your way once the port is free.