nailfile - privacy policy

last updated: may 5, 2026

we built nailfile so that almost everything stays on your phone. this page explains what does and doesn't leave your device, and why.

what we collect

• photos you add to your diary or use for try-on. these are stored on your device, not in the cloud.
• a random anonymous id we use to count your free try-ons and link your subscription. it isn't tied to your name, email, or apple id. for users signed into icloud, this id is synced through apple's icloud key-value storage so your free-try count survives reinstalls and stays consistent across your devices. apple holds the synced copy — we don't see your apple id.
• basic usage events (which screen you opened, whether a try-on succeeded, which paywall you saw) sent to posthog under the random anonymous id above. no personal content, no advertising ids, no cross-app tracking.
• subscription status and purchase history, handled by revenuecat.

we do not collect your name, email, address, contacts, location, or anything you type into your diary notes. diary notes, polish brand, salon name, and tech name never leave your device.

what happens to your photos

diary photos stay on your device. nothing is uploaded.

try-on photos are sent to our secure server only at the moment you tap generate. the server forwards them to fal.ai's hosted ai model to render the new look, then sends the result back to you. we delete try-on uploads from our server within 30 days. we don't use your photos to train any model.

third parties we use

• fal.ai — hosts and runs the ai model that generates try-on images. photos are processed temporarily, not retained for training.
• cloudflare — hosts the server that brokers try-on requests and stores temporary images.
• revenuecat — manages your subscription and credits.
• posthog (us region) — product analytics. receives event names (like "tryon_completed", "paywall_shown", or "subscription_started") and your anonymous in-app id, along with device type, app version, and country. some events come from our server — subscription state changes from revenuecat — and use the same anonymous id. we do not send your photos, diary notes, name, email, or apple id. we do not enable session replay or ad targeting.

your choices

• delete a diary entry to remove its photos from your device.
• uninstall the app to remove everything stored locally.
• email us to request deletion of any try-on images still on our server, your posthog analytics record, or to ask what we have on you.
• ios's "limit ad tracking" / app tracking transparency settings apply — we don't use idfa and don't show ads, so there is nothing to opt out of there.

children

nailfile is not directed at anyone under 13.

changes

if we change anything material we'll update the date at the top and call it out in-app.

support / contact

need help with nailfile or have a question about your data? email nailfile-support@proton.me and we'll get back to you within a couple of days.