Privacy Policy

Last updated: May 21, 2026

Short version: Professor sends your selected text to our AI service to generate an explanation. We don't store it. We don't log it. We don't know who you are. A random device ID is used only for daily rate limiting and is never linked to your identity.

1. What we collect

When you use Professor to explain text, we process:

Selected text: The word or phrase you highlighted, plus up to ~300 characters of surrounding context. This is sent to our Cloudflare Worker and forwarded to Anthropic's Claude API to generate an explanation. It is not stored on our servers after the response is returned.
Domain hint: A detected category (finance, legal, medical, technology, general) derived from the page's hostname or text content. Not stored.
A random device ID: A UUID generated in your browser and stored in chrome.storage.local. Used only to enforce the daily free-tier rate limit (10 lookups per day). It is never linked to your identity, email, or any personal information. You can clear it at any time via Settings → Clear local data.

2. What we do not collect

No account, login, or email required for the free tier
No browsing history or URLs
No keystrokes or form data
No analytics, tracking pixels, or third-party scripts on the extension
No advertising identifiers

3. Third-party services

Professor relies on the following third parties to operate:

Anthropic (Claude API): Your selected text is sent to Anthropic's API to generate the explanation. Anthropic's data usage policy applies — see anthropic.com/privacy. As of the last update, Anthropic does not use API inputs to train models by default.
Cloudflare Workers & KV: Our backend runs on Cloudflare's infrastructure. Rate-limit counters (device ID + date → count) are stored in Cloudflare KV with a 48-hour TTL. Cloudflare's privacy policy applies — see cloudflare.com/privacypolicy.
LemonSqueezy (Pro users only): LemonSqueezy is our Merchant of Record — they process payments, calculate and remit applicable taxes, and handle all card data. We receive a customer ID and subscription status; we never see your card number or billing address. See lemonsqueezy.com/privacy.
Clerk (Pro users only): Authentication for Pro accounts is handled by Clerk. See clerk.com/privacy.

4. Domain blocklist

Professor ships with a pre-populated blocklist of sensitive domains (banking portals, HR systems, password managers). On these sites, Professor does not activate and no data is sent. You can view and edit the blocklist in Settings.

5. Pro accounts

If you subscribe to Pro, we store your email address, LemonSqueezy customer ID, and subscription status in our database (Cloudflare D1) to manage your account. Lookup history for Pro users is stored to power the history feature. You can request deletion of your account data by emailing [email protected].

6. Data retention

Selected text: not retained after the API response is returned. Rate-limit counters: deleted automatically after 48 hours. Device ID: stored locally in your browser until you clear it. Pro account data: retained while your account is active; deleted within 30 days of account deletion request.

7. Children's privacy

Professor is not directed at children under 13. We do not knowingly collect personal information from children under 13.

8. Changes to this policy

We may update this policy as features change. The "Last updated" date above reflects the most recent revision. Continued use of Professor after changes constitutes acceptance of the updated policy.

9. Contact

Privacy questions? Email [email protected].