Legal

Privacy Policy

Matzu (“we”, “us”) is an AI walking-tour guide app. This policy explains what we collect, why, and the choices you have.

Data we collect

• Account: a Matzu account is required. We process your email address and an internal user ID; depending on how you sign in, we may also receive your name. You can register with email and password or sign in with Google or Apple. Stored on our backend (Supabase).
• Location: precise location, only while the app is active — in the foreground, or while an “Active Tour” notification is visible. We use it to trigger location-based narration and to plan trips.
• Voice: when you use voice mode, your microphone audio is streamed to Google’s Gemini API to generate Matzu’s responses. We do not store your audio.
• Trips & “visited” status: the trips and itineraries you create, your traveler-profile preferences, and which stops you’ve marked as visited (and roughly when). Stored on our backend (Supabase), tied to your account, and synced across your devices.
• Reports about AI output: if you report a Matzu response, we store the selected reason, a limited excerpt of the reported AI output, and any optional comment you add. The report is linked to your account and given a moderation status so we can review and handle it.
• Downloaded narrations: to prepare an offline narration, the relevant narration text is processed by Google Gemini where a script must be prepared, and the completed script is sent to Google Cloud Text-to-Speech to generate the audio. The resulting audio is downloaded and cached on your device so it can be played and replayed offline without generating it again.
• Purchases: if you buy voice credits, the purchase is handled by the app store and RevenueCat. We store your credit balance; we never receive your payment-card details.

Location, trips & “visited” history

We use your precise location only while the app is active to trigger narration and plan trips. We do not continuously track you or keep a background trail of your movements.

Your trips and which stops you’ve marked as visited are stored on our backend (Supabase), linked to your account and synced across your devices — that’s how Matzu remembers your tours and your progress, and restores them when you sign in on a new device. You can delete any trip, or delete your whole account, at any time.

How we use your data

To provide the guide, voice interaction, trip planning, downloaded narrations, purchases, and the review of reports about AI output — nothing else. We do not sell your data, and we do not use it for advertising.

Matzu is operated from Switzerland by Gian Reto Schulthess (Ottikerstrasse 34, 8006 Zürich), who is the data controller; see our Imprint for full details.

Service providers we share data with

• Google — Gemini API (voice + text), Cloud Text-to-Speech (generated narration audio), Maps/Places, and Sign-In.
• Apple — Sign in with Apple.
• Supabase — our backend, authentication, and database.
• RevenueCat — purchase management.
• Resend — sending account emails (sign-up confirmation, password reset).
• PostHog (EU-hosted) — product analytics, to understand usage and improve the app.
• Featurebase (EU-hosted, operated by CORDNET OÜ) — our public feedback board, if you post feedback, feature requests, or comments.

About Google Gemini: your voice and text prompts are processed by Google’s paid Gemini API. Under Google’s paid-API terms, this content is not used to train Google’s models and is retained only briefly for safety and abuse prevention.

Analytics & diagnostics

To understand how Matzu is used and to improve it, we collect anonymous usage and performance data via PostHog (hosted in the EU): which features you use (for example voice tools and screens, as short labels), basic device and app information (device model, operating-system and app version, language, network type), and voice-pipeline timings and error signals (for example how often you interrupt Matzu, response-time measurements, and the type and location of an error — never its message). This is tied to a random per-install identifier, not to your name or account, and is not an advertising ID.

We never send what you say to or hear from Matzu, what you ask for, your trips, or your location to analytics. Detailed crash logs stay only on your device and are not transmitted to us.

Analytics is on by default, and you can turn it off at any time in the app — Settings → “Share anonymous usage data”. We retain this analytics data for up to 12 months. PostHog processes it on our behalf in the EU.

Retention & deletion

We keep your account, trip data, and reports about AI output until you delete your account. Reports remain linked to your account while we review and handle them. You can:

• delete individual trips in the app;
• delete your whole account in the app — Settings → Delete account — which removes your account and data from our backend; or
• request deletion at matzu.ai/delete-account or by emailing [email protected].

Location is never stored as a background history; microphone audio is never stored by us. Generated narration audio is cached on your device for offline playback and may remain there until it is automatically evicted, you clear the app’s data, or you uninstall the app.

Your rights

If you’re in the EEA, Switzerland, or the UK, you have rights to access, correct, and delete your data, and to object to or restrict its processing. To exercise them, contact [email protected].

Children

Matzu is intended for adults (18+) and is not directed at children. We do not knowingly collect data from children.

Security

Data is encrypted in transit. Access to backend data is restricted.

Changes to this policy

We’ll post any changes on this page.