The 216 Tracker
216tracker.com
Co-op invitation received. Choose your tracker settings, then launch to join your partner's shared map. Crosskeys, the map, and the session's world state are required.
Downloaded edition: Connect with an invite link when online, or use connection codes for a direct connection.
This tracker saves remembered launcher settings only in your browser's local storage. Timer state stays in the current tracker window. Crosskeys co-op shares map notes with your invited partner when you connect to a session.