This extension will keep track of the anime you're watching and synchronize your Small MyAnimeList iconMyAnimeList or Small Kitsu iconKitsu accordingly.
Ranked in these QuestionsQuestion Ranking
Pro Synchronize with multiple anime platform
Emby (self hosted, highly depends on configuration)
Pro Cross platform
Available for chrome and firefox
Pro Open Source
There is github page for addons : https://github.com/TSedlar/anitrack