Legal

Privacy

Last updated 19 August 2026

This notice explains what personal data Hill Labs collects when you use our websites and applications, why we collect it, and the choices you have. It covers this site and Zipf, our language-learning app.

What we collect

• Account data. When you create an account we store the email address and identifiers supplied by our authentication provider.
• Application data. Content you create in one of our applications, so it is available to you across devices. In Zipf that means your study progress, saved words and your conversations with the AI tutor.
• Text you send to the AI. When you use translation, sentence generation, image import or the tutor, what you submit is sent to our AI provider to produce a response, together with your recent conversation for that language. Please do not put anything confidential into it.
• Billing data. If you subscribe, our payment processor handles your card details. We never receive or store full card numbers.
• Operational logs. Request metadata, timings and error diagnostics, kept for about two weeks to keep the service running and to investigate faults. We also count requests and model usage per account in order to apply fair-use limits.

What we do not do

• We do not sell personal data.
• We do not use advertising trackers, and we run no third-party analytics on this website.
• This website sets no cookies. Zipf sets only what is needed to keep you signed in — no advertising or tracking cookies.
• We do not use your content to train AI models, and our AI provider is contractually bound not to train on it either.

Processors

We rely on a small number of vendors to operate the service. Each receives only the data needed for its function:

• Clerk — accounts and sign-in (United States).
• Google — only if you choose “Sign in with Google”, which shares your name, email address and profile picture with us (United States).
• Stripe — subscription payments (United States). Card details go to Stripe directly; we never receive or store them.
• Anthropic — AI model inference for translation, conjugation, sentence generation and the tutor (United States).
• Hetzner — the server that runs Zipf, located in Germany.
• Amazon Web Services — encrypted database backups and secret storage, in Oregon, United States.
• Cloudflare — DNS and content delivery.

Where your data is processed

Hill Labs LLC is registered in Oregon, United States. Zipf itself runs on a server in Germany, so your account and study data are stored in the European Union. Backups, and the vendors listed above, are in the United States, so your data is transferred there. Where that data belongs to someone in the EEA or the UK, we rely on the European Commission’s Standard Contractual Clauses, which each of those vendors offers, as the basis for the transfer.

Retention and deletion

We keep account and application data for as long as your account is open. You can delete your account from within the application at any time — Settings, then delete your account. That immediately removes your profile, study progress, saved words, tutor conversations and usage records from our database, and deletes your login with our authentication provider.

Two things survive that deletion, and we would rather say so than let you find out later. Encrypted database backups are kept for 30 days on a rolling schedule, so your data remains in them until the backup containing it expires. And if you have ever paid us, our payment processor keeps the transaction record, because tax and accounting law requires us to be able to account for it.

Your rights

You may request access to, correction of, or deletion of your personal data. Depending on where you live you may have further rights. Email [email protected] and we will respond within the period required by applicable law.

Contact

Hill Labs — [email protected]