We use the bare minimum needed to keep you logged in. Nothing for advertising, nothing that follows you around the web.
Last updated June 2026.
A cookie is a small piece of data a website stores in your browser. Most big platforms use them to track you across the internet and sell ads. We do not. OpenBook is open source, so the exact cookies we set can be checked against the code on GitHub.
| Name | Purpose | Type |
|---|---|---|
session |
Keeps you logged in so you do not have to type your password on every page. This is essential. Without it, the site cannot know it is you. | Essential cookie |
ob_theme |
Remembers whether you chose light or dark mode. This is stored in your browser's local storage, not sent to our server, and is purely your preference. | Browser preference |
That is the whole list. If it ever grows, the change will appear in the public code history first.
We do not sell ads, so there is nothing to track you for.
No Facebook pixel, no Google ad tags, no analytics that follow you onto other websites.
We do not stitch your activity together with other sites to build a profile and sell it.
You can clear cookies any time from your browser settings. Clearing the
session cookie simply logs you out, and clearing
ob_theme just resets the site back to its default appearance.
Nothing else breaks.
This page is part of how we keep our promise that your data is yours. For the bigger picture, read our Privacy Policy and our mission.