Privacy Policy

This Privacy Policy explains how Best Day Labs ("we", "us", or "our") handles your information when you use the Keys mobile application (the "App").

1. Video imports & audio transcription

When you share or paste a video link, our servers download the audio from the source (TikTok, Instagram, YouTube, etc.) and pass it to a third-party machine-learning service (Replicate) to extract the piano part as MIDI. Audio is processed in memory and is not permanently stored on our servers. The resulting MIDI and note data are returned to your device and saved to your library.

2. Microphone (Learn Mode)

Learn Mode listens through your device microphone to detect which notes you play. Audio captured by the microphone is processed entirely on your device — it is never uploaded, recorded, or stored anywhere. The microphone is only active while Learn Mode is enabled.

3. Camera & photos (sheet music scanning)

If you use the sheet music scanning feature, the captured image is sent to a third-party AI service (Anthropic) for transcription. The image is processed in the request and discarded; we do not retain uploaded sheet music images. If you select a profile photo from your Photo Library, that image is stored locally on your device and is not uploaded to our servers unless you publish a song to the community catalog (see below).

4. Account & sign-in

Keys signs you in anonymously through Supabase Auth so your library and votes can sync across devices. If you publish a song to the community catalog, your display name and (if you set one) profile photo are associated with that contribution and visible to other Keys users. No password is collected.

5. Community catalog

If you choose to publish a transcription to the public catalog, the song's metadata (title, artist, source URL, MIDI, note data) is stored in Supabase, a third-party database and storage service. Published catalog entries are visible to all Keys users. You may request removal of your contributions at any time by contacting us.

6. Subscriptions

Keys is a paid subscription app. All payments are processed by Apple through the App Store; we do not receive or store your payment information. Subscription status is checked via Apple's StoreKit framework.

7. Local data

Your song library, playback preferences, achievements, and playback history are stored locally on your device using Apple's SwiftData framework. This data is not transmitted to us.

8. Third-party services

We use the following third parties to operate the App. Each handles your data according to their own privacy policies:

• Apple — App Store, StoreKit, Sign in with Apple.
• Supabase — authentication, database, file storage.
• Replicate — piano transcription machine-learning models.
• Anthropic — sheet music optical recognition.
• PostHog — anonymous product analytics (see section 9).

9. Product analytics

We use PostHog, a privacy-respecting product analytics service, to understand how the App is used in aggregate — for example, which features are popular, where users encounter errors, and how the import flow performs. The events we record describe interactions (e.g. "import succeeded", "learn mode started") and are keyed only by your anonymous Supabase user ID. We do not collect screen recordings, full keystroke logs, advertising identifiers, location data, contacts, or browsing history outside the App. We do not use this data to track you across other apps or websites.

10. Children's privacy

The App is rated 4+ and may be used by people of any age, but we do not knowingly collect personal information from children under 13 beyond what is necessary to provide the App's core functionality.

11. Your rights

You can delete your Keys account and associated catalog data from within the App (Profile → Account → Delete Account), or by emailing us at the address below.

12. Changes to this policy

We may update this Privacy Policy from time to time. The "Effective" date above will reflect the most recent update. Continued use of the App after changes means you accept the revised policy.

13. Contact

If you have any questions about this Privacy Policy, please contact us at support@bestdaylabs.com.