Privacy policy
Last updated 3 August 2026.
Fuego is an AI language tutor. To teach you, it has to store what you say to it. This page states exactly what that means: every category of data we keep, every company that sees it, where it sits, how long it stays, and how to make us delete it.
Questions about anything below go to privacy@heyfuego.com.
What we collect
Account
You sign in with Firebase Authentication. We store the Firebase user ID, the email address attached to it, and the display name if your sign-in provider gives us one. We never receive or store your password. There is no guest mode: an account is required to use the app.
Learning profile
Your native language, the language you are learning, your time zone, your self-reported level, and the results of the placement test. The tutor also builds a memory of you from your conversations: your goals, your interests, your recurring mistakes, and preferences you state out loud. We keep a version history of that memory. You can read and correct it inside the app.
Conversations
Every chat message you send and every reply the tutor gives, stored as text. This includes voice sessions: the spoken conversation is transcribed and the transcript is saved as text in the same place as your typed chats.
Practice
Your flashcards and their review schedule, the exercises generated for you, the answers you submit, and the proficiency estimates we derive per skill over time.
Device and billing
If you allow notifications, we store a push token and the platform it belongs to. If you subscribe, we store your plan, the trial and renewal dates, your remaining voice minutes, and the store transaction identifiers we use to avoid granting the same purchase twice.
Feedback
If you send feedback from inside the app, we receive your message, the email address you type in, your platform, app version, and locale.
Voice and audio
We do not store your recordings. Audio is streamed live and then gone. What survives is the text transcript.
Fuego offers two voice modes, and they route your audio differently.
- Default mode. Our server mints a short-lived token, and your device then streams audio straight to Google's Gemini Live API. Our servers never receive the audio.
- Pipeline mode. Your audio streams to our voice relay in Germany, which passes it to Soniox for speech recognition, to Google for the tutor's reply, and to ElevenLabs or Google for the spoken answer. The relay holds no database and writes no files. Audio passes through memory and is discarded.
In both modes, only text comes back to us: the transcript lines and the number of seconds you spoke, which we count against your plan.
Audio the tutor speaks in listening exercises is synthesised, cached in Cloudflare R2, and shared between learners who get the same sentence. That cache holds no recording of you.
How we use it
- To run the tutor: your profile and conversation history become the context we send to the language model.
- To generate lessons, exercises, and flashcards pitched at your level and your weak spots.
- To track your streak, your progress, and how many voice minutes you have left.
- To send push notifications you asked for.
- To answer your support messages.
- To find crashes and fix them.
We do not sell your data. We do not share it with advertisers. We do not use your conversations to train our own models.
Companies that process data for us
Each of these sees part of your data to do a job for us. None of them may use it for their own purposes.
| Company | What it receives | Why |
|---|---|---|
| Google (Firebase) | Your email, sign-in identifiers, push token, crash reports tagged with your user ID | Sign-in, notifications, crash reporting |
| Google (Gemini) | Your messages, your learning profile, your tutor memory, and your live audio in default voice mode | Generating the tutor's replies, exercises, and speech |
| Soniox | Your live audio, in pipeline voice mode only | Speech recognition |
| ElevenLabs | The tutor's reply text, in pipeline voice mode only | Speaking the reply aloud |
| RevenueCat | Your user ID and your App Store or Play Store purchase records | Managing subscriptions |
| Cloudflare | Requests to this website; cached synthesised lesson audio | Serving the site and lesson audio |
| Hetzner | Everything in our database, as the operator of the server it runs on | Hosting |
| Telegram | Feedback you send us, and transcripts of voice sessions | Alerting us to problems and reviewing tutor quality |
| Anthropic | Nothing today | Configured as an alternative tutor model but switched off. We will update this page before we turn it on. |
Apple and Google also process your payment when you subscribe. We never see your card number.
Where your data is stored
Our database and our voice relay run on a Hetzner server in Falkenstein, Germany. Backups are copied to Hetzner Storage Box, Cloudflare R2, and Backblaze B2. Our processors are global companies, so your data does reach servers outside the European Economic Area, in particular in the United States.
How long we keep it
Be clear on this one. Nothing expires on a schedule today. Your conversations, transcripts, flashcards, and tutor memory stay until you ask us to delete them or you delete your account.
Backups are kept for 7 days, 4 weeks, and 3 months on a rolling basis. So for up to roughly three months after a deletion, a copy can still exist inside a backup we cannot edit. Those copies are not used to serve the app and roll off on their own.
Your rights
If you are in the UK, the EEA, or a US state with a privacy law, you can ask us to show you your data, correct it, export it, delete it, or stop a particular use of it. You can complain to your national data protection authority.
Email privacy@heyfuego.com from the address on your account. We answer within 30 days. There is no charge.
For deletion, follow the steps on the account deletion page. It says what gets removed and what does not.
Our legal basis, if you are in the EEA or the UK
- Contract. Running the tutor, storing your progress, and managing your subscription. Without this data there is no product.
- Consent. Push notifications, and the microphone. You grant both at the OS level and can withdraw either in your phone's settings.
- Legitimate interests. Crash reporting, abuse prevention, and reviewing tutor output for quality.
Children
Fuego is not built for children. Do not use it if you are under 13, or under the minimum age of consent where you live if that age is higher. We do not knowingly collect data from children. If you believe a child has an account, write to privacy@heyfuego.com and we will delete it.
Security
Traffic runs over TLS. Sign-in is handled by Firebase, so we never hold a password. Access to the production database is restricted to the operator over a private network, and the server does not accept public SSH.
No system is perfect. If you find a security problem, email security@heyfuego.com and give us a way to reach you.
Changes
When this policy changes we update the date at the top. If a change means we start doing something materially different with your data, we will tell you in the app before it takes effect.
Contact
privacy@heyfuego.com for anything on this page. support@heyfuego.com for everything else.