Privacy Policy for b2fit

Last updated: November 6, 2026

This policy explains what data the b2fit Android app and the b2fit server (b2fit.b2ss.com) process, why, and who receives it. b2fit is a free hobby project run by a private individual (contact below).

1. Data stored on your device

Your fitness data (food logs, weight, fasting, water, habits, mood, workouts), your AI conversations and the app's knowledge about you are stored only on your device. You manage them with the app's backup and restore features. We have no copy of them.

2. AI features

AI features are optional. When you use them, the text you write, the photos you choose for food analysis, and a summary of your recent fitness data that the app adds as context are sent to an AI service. Which service depends on the AI option you select in the app:

2.1 Your own provider (your own API key)

If you enter your own API key (for example OpenAI or OpenRouter), requests go directly from your device to that provider. We do not see them. That provider's own privacy policy and terms apply.

2.2 Poor man’s AI

Poor man’s AI lets you use the AI features without an API key. It is only used after you accept its explanation in the app. When it is active:

• Your requests (text, photos and the fitness context described above, which can include health data) are sent to the b2fit server, which forwards each one to one of several third-party AI providers that offer free usage. The provider can change from one request to the next.
• These providers may store your requests and, depending on their terms, may use them to improve or train their models. Their own privacy policies apply. The providers we currently use are listed at the end of this section.
• The b2fit server does not store the content of your requests or the answers. It stores only technical metadata: time, which feature was used, which provider and model answered, whether it succeeded, how long it took, token counts, your optional 👍/👎 rating, and a pseudonymous ID of your app installation. This is kept for at most 90 days and is used to enforce daily limits, prevent abuse and decide which providers to keep.
• To check that requests come from the genuine b2fit app and to apply limits per installation, the app uses Google Firebase App Check (Play Integrity) and Firebase anonymous sign-in. This creates a random installation ID with no name, email or phone number attached.
• The b2fit website and server are reached through Cloudflare, which processes the traffic, including request content, in transit.
• Answers can be wrong. They are not medical advice.

Current providers: none yet. Poor man’s AI is not available in the app yet; this list is filled in before it is.

You can stop using Poor man’s AI at any time in the app's AI settings; nothing more is sent after that. The legal basis is your explicit consent, which you give by accepting the explanation in the app (GDPR Art. 6(1)(a) and 9(2)(a)). Withdrawing it does not affect requests already made.

3. Voice

Voice input uses your device's speech recognition. Spoken answers use your device's text-to-speech, or the OpenAI speech service if you use your own OpenAI key.

4. Analytics

The app uses Firebase Analytics for app usage events, device and OS information, and crash and performance diagnostics. This does not include your fitness data or AI conversations.

5. Advertising and sale of data

b2fit shows no ads, uses no advertising identifiers, and does not sell, rent or trade your data.

6. Recipients and transfers

Depending on what you use: the AI provider you configure; the providers used by Poor man’s AI; Google (Firebase Analytics, App Check, anonymous sign-in); Cloudflare; and our server hosting provider. Some of these process data outside the EU, under their own safeguards such as the EU–US Data Privacy Framework or standard contractual clauses.

7. Children

If you are under 16, ask a parent or guardian before using Poor man’s AI or any other AI feature.

8. Your rights

You can ask for access to, correction or deletion of the metadata linked to your installation ID, and you can complain to your data protection authority (in Hungary: NAIH, naih.hu). Your on-device data is in your hands: deleting the app or its data deletes it.

9. Changes

We update this page when the app or server changes and change the date at the top. If Poor man’s AI changes in a way that matters, the app asks you to accept the explanation again.

10. Contact

[email protected]