The best open source alternative to Tonkatsu Box is SeriesGuide. If that doesn't suit you, we've compiled a ranked list of other open source Tonkatsu Box alternatives to help you find a suitable replacement. Other interesting open source alternative to Tonkatsu Box is Showly.
Tonkatsu Box alternatives are mainly Personal Tracking Apps. Browse these if you want a narrower list of alternatives or looking for a specific functionality of Tonkatsu Box.
Android app for tracking TV shows and movies you're watching, have watched, or plan to watch, powered by TMDb data.

SeriesGuide is an Android app for anyone who watches a lot of TV and wants a reliable way to track what they've seen, what's airing next, and what's on their watchlist. It pulls data from TMDb to keep show and movie information current.
At its core, it's a personal viewing log. You mark episodes as watched, follow release schedules, and manage a list of shows and films you plan to get to. If you've ever lost track of where you left off in a series, or forgotten whether you've already seen a movie, this solves that problem.
The app is built specifically for Android, so it fits naturally into the mobile experience rather than being a web tool bolted onto a phone. It's a solid open source TV Time alternative for people who prefer not to rely on closed, account-heavy platforms for something as simple as tracking their watch history.
Because it's open source, the code is publicly available and the project is community-supported. There's no black box around how your data is handled, and the app doesn't depend on a proprietary backend that could disappear or change terms without notice.
Looking for open source alternatives to other popular services? Check out other posts in the alternatives series and openalternative.co, a directory of open source software with filters for tags and alternatives for easy browsing and discovery.
Android and iOS app for tracking TV shows and movies, managing watchlists, and syncing viewing history with Trakt.tv across devices.

Showly is a TV show and movie tracking app for Android and iOS, built around a clean interface and tight Trakt.tv integration. It's aimed at anyone who wants a single place to manage what they're watching, what they've watched, and what's coming up next.
The core loop is straightforward: browse trending and curated titles, mark episodes and movies as watched, and build out a collection over time. Showly separates your Watchlist (things you plan to watch) from your Collection (things you've seen), which keeps your library organized without much manual effort.
Key capabilities:
The Trakt.tv integration is the standout feature for serious trackers. Trakt is a widely used open platform for logging watch history, so connecting Showly to it means your data isn't locked into a single app. You can switch clients or use multiple apps without losing your history.
With over 80,000 users, Showly has built a following largely on its interface quality. The UI is consistently cited as one of its strengths, which matters in a category where many alternatives feel cluttered or dated.