Lexicon Privacy Policy

Last updated November 3, 2026. Lexicon is published by Quartzi, Chicago, Illinois ("we").

In short: Lexicon has no ads, analytics or tracking. If you make a Lexicon account at app.getlexicon.org, we keep your email address and your notebook so you can use them, and nothing else; you can delete both at any time. If you connect the app to a server you run yourself, we receive nothing at all.

What the app is

Lexicon is a notebook for words and quotes. You can keep it in a Lexicon account that we run at app.getlexicon.org, on a Lexicon server that you run yourself, or on one that someone you trust runs for you. You can also try the iOS app with sample data in a demo, with no server at all.

Lexicon accounts

When you make an account at app.getlexicon.org, we store:

Your email address and a one-way hash of your password. We never store the password itself.
Your notebook: the words, quotes and everything else listed under "What goes to your server" below. Each account's notebook is kept in its own file, and no other account can see it.
Your sign-in tokens, stored only as hashes, with the name you gave each one, when it was made and the day it was last used. Your browser's time zone is saved when you sign up so the word of the day changes at your midnight.

We use this only to run your account. We don't sell it, share it, show it to anyone or use it for advertising, and we don't send you marketing email. To limit password guessing, the server remembers the network address of failed sign-ins and new sign-ups for up to an hour. Requests reach the server through Cloudflare, which handles them as our network provider.

Everything said below about "your server" applies to app.getlexicon.org, with us as its operator.

The demo

"Try the demo" uses sample words and quotes built into the app. Anything you add or change is held in memory on your device and is gone when the app restarts. The app sends nothing over the network in the demo, apart from a link you tap or something you choose to share, as described below. Starting the demo removes any saved token. Your demo words aren't saved; the app keeps only the settings listed below.

What stays on your device

In the iOS keychain, shared with Lexicon's widgets and share sheet: your server address, your access token, the most recent word and quote of the day (so widgets can show them offline), and the demo setting.
In the app's settings: whether Fill runs when you add a word, and a note of which tab to open next.

What goes to your server

When you connect, the app sends your server the things you ask it to save or look up, always with your access token:

Words, meanings, quotes, sources, tags and notes
Review grades, searches, and sentences you ask it to check
The AI provider, model, API key and time zone you enter in Settings. The key is stored on your server and only its last four characters ever come back to the app.

All of this goes directly from your device to the address you entered. We can't see it. Whoever operates that server is responsible for it.

What your server sends onward

A standard Lexicon server contacts other services only when you use these features:

Fill looks the word up in the Free Dictionary API.
Fill sends the word, and its meaning and part of speech if they are already known, to the AI provider you chose, using your key, if you set one up. Check my sentence sends the word, its meaning and your sentence the same way. That provider's own privacy policy applies. Without one, nothing goes to any AI provider.
The model list and Test in Settings contact that AI provider with your key, and send none of your words.

The server's log records the method, path, status and duration of API requests and of any failed request. It doesn't record search terms or the contents of normal requests, though an unexpected server error writes the error's details to the log, and those could include some of your data. Any reverse proxy or tunnel in front of the server keeps its own logs.

Removing your data

Disconnect in Settings removes the token and the saved word and quote of the day from your device. Your server address stays, so you can reconnect.
Words and quotes on the server stay there after you disconnect. Delete them in the app before disconnecting, or have the server's operator delete them.
Deleting the app removes its settings. iOS can keep keychain items, including your server address, after an app is deleted, so disconnect first if that matters to you.

Your Lexicon account: in the web app, Settings › Delete account and notebook removes your account, its tokens and its notebook from the server straight away. Backup copies are deleted within 14 days. You can also export everything as Markdown first, under Settings › Export Markdown.

If you only use your own server, we hold none of your data, so we have nothing to delete or hand over.

Permissions, sharing and links

The app doesn't ask for your location, contacts, photos, camera or microphone, and it doesn't read advertising or device identifiers. iOS may ask for permission to use your local network, which is only used to reach a server address you enter.

If you share a word or quote through the iOS share sheet, it goes to the app you pick. Links to this page and our support page open in Safari, where the website's host sees an ordinary web request.

If you turn on sharing with app developers in iOS settings, Apple may give us crash reports and usage statistics. These don't identify you to us.

Children

Lexicon isn't directed at children under 13, and we don't knowingly collect anyone's personal information.

Changes

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

Contact

Questions: jake@quartzi.ai.