Privacy

Short version: your reading is yours. Lumen stores what you choose to save so it can show it back to you. It never sells or rents your data, never uses it for advertising, and lets you export or delete everything at any time.

What we store

• Your account: name, email and avatar from Google or GitHub when you sign in with them.
• What you save: links, the readable text of those pages, highlights, notes, collections, tags and reading progress.
• Activity used for your streak and analytics (what you did and when, in your account only).
• Blogs you follow, and their new posts.
• Destination settings. Notion tokens and webhook secrets are stored encrypted at rest by our host and are never returned by the API. Your Obsidian API key never leaves your browser.
• Access tokens you create, stored only as a hash, with how often an agent used them and which tool it used last.
• Share links you create: a copy of exactly what you chose to share and its preview image. They are public to anyone with the link until you delete them.

The browser extension

The extension can see the pages you open, because it has to draw your highlights and its toolbar on them. It does not record your browsing, and it sends nothing about a page unless one of these is true:

• You act on it: highlight, note, save, ask, explain, summarise, follow, or open the popup or panel. Then it sends what that action needs: the address and title of the page, its readable text when you save or highlight it, and the selected passage with its paragraph when you ask about it.
• You already highlighted that page: to bring your highlights back. The extension keeps a list of your highlighted pages in the browser and checks it first, so pages you never marked are never sent to us.

Without a Lumen account, highlights stay in your browser. Settings, your choice of AI provider and any API key you enter for it stay in the browser too. In the background, the extension only checks for reading reminders and new posts from blogs you follow; that sends no page data.

AI

Lumen's hosted answers run on Cloudflare Workers AI: the passage or question and the context needed to answer it are sent there to generate the reply. We keep a daily count of answers for the quota, not the prompts or the answers. In the extension you can choose another provider instead, and then the text goes only there: Ollama on your own machine, an OpenAI compatible service with your own key (under that service's terms), or Claude through the Lumen helper on your computer. Ask always uses Lumen, because your library lives here.

Agents

An agent you connect over MCP (Claude Code, Cursor and others) can read and change your library with the same rights as you, and nothing else. Disconnect it any time; its key stops working at once.

Readers like you

If anonymous signals are on (the default), the fact that you saved a public URL can count toward "readers like you also saved this" for others. Only URLs saved by at least two other readers are ever shown, never who saved them, never your highlights or notes. Turn it off in Settings.

Product analytics

To learn which parts of Lumen help and where people get stuck, we use PostHog, hosted in the EU (Frankfurt).

• On the website, only with your consent. If you allow it, PostHog records the pages you visit, the buttons you press and how long you stay, and may record anonymised session replays. Inside the app, the text on screen (your library, highlights and notes) and everything you type are hidden in those recordings. If you say no, PostHog is not loaded at all. Change your answer any time in Settings.
• Usage counts from our server. When you sign up, save, highlight, ask the assistant, connect the extension or an agent, or pay, our server sends PostHog an event with your account id, the action and where it came from (web, extension or agent). Never your email, page text, highlights, notes, questions or answers. This is how we count usage by feature, under our legitimate interest in running and improving the service.
• The extension contains no analytics code.

Preventing abuse

Each person gets one free Pro trial. To enforce that and to protect the free AI allowance, we keep a hashed form of your email, of your network address and of a random device id stored in a first party cookie, and use them only to decide whether a new account gets a trial and to limit how many accounts one network can create in a day.

Who processes it

Cloudflare hosts everything (Workers, D1 in Western Europe, Workers AI). Google or GitHub sign you in if you choose them. PostHog (EU) receives the analytics described above. If you pay for Pro, Stripe handles the payment; we never see your card. There are no advertising trackers on the site or in the extension.

Chrome Web Store

Lumen's use of information received through the browser extension complies with the Chrome Web Store User Data Policy, including the Limited Use requirements. That information is used only to provide the features described here, is never sold, never used for advertising or credit decisions, and is never read by people except with your permission, for security, or where the law requires it.

Your controls

Export JSON from Settings, export collections as markdown, delete share links, revoke tokens and agents, and delete your account, which removes every row immediately. Demo sandboxes are deleted after three days. Questions: open an issue.

Updated 2026-11-01. Lumen is in public preview.