Last updated: June 22, 2026
Mastery Timer is local-first. You can use the whole app, track every skill, and reach mastery without ever creating an account. Data only leaves your device if you choose to sign in for cloud backup or the optional Friends feature.
By default, your skills, daily goals, lifetime hours, ranks, streaks, session history, and settings are stored only on your device. If you never sign in, none of it is transmitted anywhere, and there is no advertising, no third-party analytics, and no tracking across other apps or websites.
Signing in is optional, and it enables two things: backing up your progress so you can restore it on a new device, and the Friends feature. When you sign in, we collect and store the following so those features can work:
The Friends feature is an optional one-time purchase. If you use it, people you accept as friends can see your display name, username, your skills and their lifetime hours, and your current streaks. A global leaderboard ranks signed-in users by total lifetime hours and shows your display name or username alongside that total. You can turn off discoverability in the app so others cannot find you by username search.
When you use an account, a small number of providers process this data on our behalf:
We do not sell or rent your information, and we do not share it for advertising.
On-device data stays until you delete the app. If you created an account, you can delete it at any time in the app under Friends, then Account, then Delete account. Deleting your account permanently removes your profile, your backed-up skills, your friendships, and your cheers from our servers. Your on-device history remains on your phone unless you also delete the app.
Mastery Timer is not directed to children under 13 and we do not knowingly collect personal information from children under 13.
If we change what the app collects or how it is used, we will update this page before those changes ship.
Questions, or a request to access or delete your data: [email protected]