Privacy
Last updated November 13, 2026
Margin is built so your study notes never leave your computer. This page explains exactly what it stores and the one situation in which it goes online.
What Margin stores
Your courses, terms, definitions, quiz progress, recent PDFs and settings are saved in Chrome's local extension storage, inside your own browser profile. There is no Margin account, no server and no sync. Uninstalling Margin deletes everything, so use Settings → Export if you want a backup.
What Margin sends over the internet
Only one feature makes network requests: Find one, on the card you see when saving a term. While it is open, Margin asks these public services for definitions of that term:
| Service | What is sent |
|---|---|
| Wikipedia | The term and a subject word, for example “heap computer science”. |
| Wiktionary | The term. |
| EMBL-EBI Ontology Lookup Service | The term, for statistics, biology, chemistry and medicine courses. |
| MeSH, U.S. National Library of Medicine | The term, for biology, medicine and psychology courses. |
Nothing else is sent: not the page you are on, its text, your course names, your glossary or any identifier. Answers are cached on your computer. Textbook (OpenStax) and computer science (NIST) definitions are built into the extension and need no connection. If you only use Write my own, Margin makes no network requests at all.
When you open a web PDF, Margin's viewer downloads it from its original address, the same way Chrome's built-in viewer would.
Suggested terms in the PDF viewer are found on your computer, by comparing the PDF's text with glossaries and word lists built into Margin. The PDF's text is never sent anywhere, and there's no AI service involved.
Permissions
| Permission | Why Margin needs it |
|---|---|
| Storage | To keep your glossary on your computer, without a size cap for big courses. |
| Access to websites | To underline your saved terms on school and learning sites (and any site you turn on), to save a term from any page, and to fetch definitions for Find one. On other sites Margin stays inactive by default. |
| Context menus | For the right-click “Save to Margin” option. |
| Web requests | To notice when a tab opens a PDF, so it can open in Margin's viewer. Only used after you turn on Open PDFs in Margin. |
No tracking
Margin has no analytics, no ads, no remote code and no third-party scripts. This website doesn't use cookies or analytics either.
Questions
Margin is open source, so you can read every line on GitHub. For questions, open an issue.