When you upload your Letterboxd export ZIP, the file is processed on our server in memory to read watched.csv. We do not permanently store the ZIP file itself.

We store the list of movies you have watched, along with locally cached posters for each movie (to improve performance and reduce external requests).

Your battle votes are stored and used to calculate Elo ratings and to power the personal and public leaderboards. Votes are associated with an ID stored in a browser cookie and may include your Letterboxd username if it appears in the ZIP filename. You can clear this at any time by deleting cookies or using "Delete Session" in the profile menu.

We also record the time between presenting a pair and your vote (in milliseconds) to help detect automated activity.

This site uses publicly available endpoints from TMDB and Letterboxd but is not endorsed by them.