Estrix privacy policy

Last updated: 1 November 2026

Estrix is an app for viewing, editing, and reasoning over OWL ontologies on iPhone, iPad, and Mac. This policy explains what happens to your information when you use it. Estrix LLC makes Estrix, and 'we' and 'us' in this policy mean Estrix LLC.

The short version

• Estrix works on your device. You don't need an account.
• We don't run servers that receive your data, and we don't collect analytics, use advertising, or track you.
• Your data leaves your device only when you use a feature that needs the internet. It then goes directly to the service involved, never to us.

What stays on your device

Everything you open or create in Estrix stays on your device: the ontologies, your edits, reasoning results, copies of downloaded files, and your settings. The app keeps them in its own private storage, and deleting the app deletes them.

If you add an API key for a cloud AI provider or connect a GitHub account, the app stores that key or token in your device's Keychain. You can remove a key in the app's AI settings, or sign out of GitHub, at any time.

When Estrix connects to the internet

Estrix connects to the internet only in the cases below.

Opening ontologies from the web. When you open an ontology from a web address, or open one that imports other ontologies, the app downloads those files from the servers that host them, such as w3.org, purl.obolibrary.org or github.com. As with any web request, those servers see your device's IP address and the address of the file requested, and their own privacy policies apply. The reference ontologies bundled with the app open without a connection, and the app keeps downloaded copies so it can reopen them offline.

Ask, with a cloud AI provider (optional). Ask answers questions about your ontology. By default it uses Apple's on-device model, and nothing leaves your device. If you choose a cloud provider in the app's AI settings (currently Anthropic's Claude or Google's Gemini) and add your own API key, your question and relevant ontology content go to that provider to generate the answer. Depending on the feature, that content includes entity names and labels (classes, properties, and individuals), the asserted and inferred axioms of the entities involved, and query or graph results, including any literal data values they contain. The provider's terms and privacy policy govern how it handles that content.

GitHub (optional). If you connect a GitHub account by pasting a personal access token, the app reads the files you link to it. When you choose to save, it commits your edits to your repository and can open a pull request. These requests go directly to GitHub under your account, and GitHub's privacy statement applies.

Siri and Shortcuts. When you use Estrix through Siri, Apple processes your voice request under Apple's privacy policy. The app's own work for that request runs on your device, except that a question to Ask uses whichever AI backend you have chosen.

What we receive

We receive nothing automatically. Estrix contains no analytics, advertising, or third-party crash-reporting code, and it reads no advertising identifier. Its diagnostic logs stay on your device.

We receive information about you only in two cases:

• Feedback you send. If you send feedback from the app, your mail app opens a message to us. We receive whatever you choose to send, along with your email address, and use it only to reply and to improve the app.
• Reports Apple shares. If you agreed to share analytics with app developers in your device's settings, or if you test Estrix through TestFlight, Apple may share crash reports, feedback, and screenshots you submit, and basic device information with us. Apple's privacy policy covers that sharing. We use those reports only to fix and improve the app.

Children

Estrix is not directed at children under 13, and we don't knowingly collect information from them.

Your choices

• Keep Ask on the on-device model, or don't use Ask at all, and no ontology content leaves your device.
• Remove a stored API key, or sign out of GitHub, in the app's settings.
• Delete the app to delete everything it stored on your device.
• Email us to ask about, or delete, any feedback you have sent.

This website

estrix.app is a set of static pages served by GitHub Pages. The pages set no cookies, run no scripts, and use no analytics or third-party fonts, so the site itself collects nothing. GitHub, which hosts it, may log visitors' IP addresses to keep its service secure, as GitHub's privacy statement describes.

Changes to this policy

If this policy changes, we will update this page and the date at the top.

Contact

Estrix LLC is responsible for the information it receives as this policy describes. Questions about this policy, and requests about feedback you have sent: privacy@estrix.app. Help with the app: support@estrix.app.