Mailmargin Privacy Policy
Last updated: 15 October 2026
Mailmargin ("the extension", "we", "us") is a Chrome extension that lets you add private notes to Gmail threads. It is provided by Nicholas Syrianoudis, who is the controller for the limited personal data described here. Contact: support@plankfoundry.com. Website: https://plankfoundry.com/mailmargin/. Postal address available on request at support@plankfoundry.com.
1. The short version
Your notes are stored only in your own browser. We run no server for the extension, it sends nothing to us or anyone else, and we cannot see your notes. There is no account, no sign-in and no payment.
2. What the extension reads in Gmail
On mail.google.com the extension reads only the ID of the thread you are looking at, from the page address or from the thread rows in your inbox list. It uses that ID to attach your note and to show which threads have a note. It does not read, copy or store email content, subjects, senders or recipients. It does not use the Gmail API and requests no Google account permissions (OAuth scopes).
3. What the extension stores, and where
Everything is kept in your browser's local extension storage (Chrome's storage.local) on that computer:
| Data | Why |
| For each note: the thread ID, the note title and text you type, the colour tag, any date and the open/done status you set, and the time it was last changed | To show and search your notes |
Notes are not synced to your other computers or to your Google account, and they do not appear in the Gmail mobile app. Storage is capped at about 9 MB: if saving a note would take your notes over that limit, the extension does not save it and tells you to delete or export older notes first.
Uninstalling the extension, or clearing its data in Chrome, deletes your notes permanently. We cannot recover them because we never have a copy.
4. Export and import
You can export all your notes to a JSON file and import a file you exported earlier. These files are created and read on your computer only; we never receive them. Keep exported files safe, because they contain your note text.
5. Browser permissions
- storage: to save your notes in your browser.
- Access to mail.google.com: to read the thread ID and show the note panel and note markers in Gmail.
6. What we do not do
We do not collect analytics, use cookies, track you, show ads, or sell or share any data. The extension makes no network requests of its own.
7. If you email us
If you write to support@plankfoundry.com, we receive your email address and whatever you choose to send. We use it only to answer you and keep it only as long as needed for that and any follow-up. Our email is hosted by Google, which processes it under its own terms.
8. Your rights
Your notes are under your control in your browser: you can edit, export or delete them at any time. For anything we hold about you (in practice, support emails), you can ask us to access, correct or delete it, or object to how we use it, by writing to support@plankfoundry.com, depending on the laws where you live (including the EU/UK GDPR and US state privacy laws). For support emails, our legal basis (EU/UK) is our legitimate interest in answering you. You can also complain to your local data-protection authority.
9. Children
The extension is not directed at children under 13 (under 16 in the EU/UK).
10. Changes
If we change how the extension handles data, we will update this policy and the date above before the change takes effect.
11. Trademarks
Gmail is a trademark of Google LLC. Mailmargin is not affiliated with, endorsed by, or sponsored by Google.
12. Contact
Nicholas Syrianoudis. Email: support@plankfoundry.com. Postal address available on request at support@plankfoundry.com.