Tanli is built with no sign-up or login and as little data collection as the app can function without. This page explains, plainly, what that means in practice. It's a companion to our Terms of Service, which covers UV exposure risk and other terms of use.
Information we collect
Location
Your device's coordinates, while you're using the app, sent to Tanli's backend to look up the real-time UV Index for where you are, so the app can show the current UV Index and save it with sessions you log. The latest coordinates we received are stored with your anonymous account. On your phone, Apple's location services turn them into a city name to label the reading; we don't store your street address.
Photos
Your reference photo, used to generate your tan previews, and any check-in photos you take in the app, which are compared with your starting photo to show how your skin looks over time. They are stored in a private location tied only to your own anonymous account. Along with a photo, our server receives a black-and-white outline of where you are in the frame, drawn on your phone by Apple's built-in person detection so the tan is only applied to you; it is used while your previews are made and is not stored. Photos in your Bulletin tan diary stay on your device — if you share one, you choose where it goes. Each check-in photo is also pinned to your diary as a separate copy that stays on your device; the check-in photo itself is stored with your account as described above, and removing the diary copy doesn't delete the check-in.
Skin answers
Your reported burn tendency and whether you're currently tanned, used to tailor your tan previews (for example, the darkest shade isn't offered if you tell Tanli your skin always burns); your burn tendency also sets the daily sun-limit warning. Tanli no longer asks new users about SPF use or sun sensitivity. If an earlier version asked you whether you regularly use SPF, or about photosensitizing products or past severe sun reactions, those answers stay on your device, the app no longer sends them to our servers, and it clears any copy an earlier version sent the next time it updates your skin answers or chosen shade there.
Sessions you time or log
If you use the timer or log time outside, the start and end time, length, average UV Index for that time, any sunscreen you noted, and whether you timed it or entered it afterwards, kept as your own history. Sessions never count toward your tan progress, which comes only from your photos.
An anonymous device ID
Tanli has no sign-up or login. On first launch we create an anonymous account (via Firebase Authentication) so your data can sync and persist — it isn't tied to your name, email, or any other real-world identity unless you choose to enter your first name in Settings.
First name (optional)
Only if you type one into Settings, used solely to personalize the dashboard greeting.
Purchase status
Whether you have an active subscription and which plan, so the app can unlock the right features. Actual payment handling (card details, billing) is done entirely by Apple — Tanli never sees or stores payment information.
We do not collect your name, email address, or contacts unless you voluntarily type your first name into Settings. We do not use advertising or analytics SDKs of any kind, and we do not sell or rent your data to anyone.
How your information is used
To generate your tan previews from your reference photo, and to check that each preview looks right (for example, that only your skin was tanned).
To compare your check-in photos with your starting photo, so you can see how your skin looks over time.
To show the current UV Index for your location, and save it with sessions you time or log.
To tailor your tan previews to your skin answers.
To tell you to get out of the sun if the sessions you've logged in a day reach a limit for your skin type.
To remember your history and preferences between app launches.
Who we share it with
Tanli's backend runs on Google Firebase (authentication, database, file storage, and server functions), which is where your photo is turned into your tan previews. A few other services process data only as needed to deliver a specific feature, and never receive more than that feature requires:
Google's Gemini API receives a reduced-size copy of your photo, next to a copy with the tanned area highlighted, so it can check each preview for mistakes. If a preview fails that check, Gemini may also receive your photo in order to generate that preview instead.
OpenAI's API is a backup for those same two jobs: it receives the same images only when Gemini is unavailable. When it is asked to generate a preview it may also receive a short note about your skin type.
Apple WeatherKit receives your coordinates from our backend, solely to return the UV Index for that area. If that lookup isn't available, the app may send your coordinates to Open-Meteo, a public weather service, as a fallback for the same purpose.
We send these images from our server, not from your phone, and without your name or account ID. The reduced-size copies used for checking are not stored by Tanli.
None of these are advertising or data-broker services, and none of them receive your photo, location, and identity together as a combined profile.
Data retention & deletion
Your data is kept for as long as you use Tanli. You can delete it yourself at any time in the app under Settings > Delete Account, which permanently deletes your reference and check-in photos, previews, history, and stored profile data from Tanli's servers and from your device. If you can't use the app, email dillonkeating20@gmail.com and we'll delete it for you. Photos in your tan diary, including the copies of your check-in photos, are only on your device: you can remove them any time in the app, and deleting Tanli removes them. Removing a check-in photo from your diary doesn't delete the check-in. Check-in photos stored with your account are deleted when you delete your account.
Your rights & choices
Wherever you are, you can ask us to access, correct, or delete the data described above by emailing dillonkeating20@gmail.com — we'll respond and act on it, without a fee, generally within 30 days. If you're a California resident, this covers the access, deletion, and correction rights the CCPA gives you; if you're in the UK, EU, or another jurisdiction with its own data protection law, it covers the equivalent rights there. We don't sell your data or use it for cross-context behavioral advertising, so there's no "opt out of sale" toggle to offer — there's simply nothing being sold. You can also revoke location or photo library access at any time in your device's Settings; the app will keep working, with UV data or photo features unavailable until you turn access back on.
Children's privacy
Tanli is not directed at children under 13, and we do not knowingly collect data from children under 13. If you believe a child under 13 has given us data, email dillonkeating20@gmail.com and we'll delete it.
Changes to this policy
If this policy changes in a meaningful way, the "Effective" date at the top of this page will be updated.