Sanctum
Privacy Policy
Last updated 8 September 2026
Sanctum does not collect, transmit, or sell any data.
What it stores
Everything Sanctum saves is written to your browser's local extension storage on the device you are using.
- Your allowed-site list
- The domains you added. Kept until you remove them.
- Your current focus session
- When it started, when it ends, whether it is locked or paused. Kept until the session ends.
- Daily counters
- How many times Sanctum blocked something each day, how long you focused, and which hostnames were blocked — the 50 most frequent per day. Kept for 30 days, then dropped automatically.
- Host totals
- A running block count for your 50 most-blocked hostnames.
The counters are what the popup shows you under "Blocked today". They exist so that you can see your own habits. They are readable only by Sanctum, only on that machine. Uninstalling deletes all of it.
What it reads
To decide whether a site is blocked, Sanctum reads the
hostname of the page you are opening —
example.com, not the full address and not the query string.
That comparison happens on your device, in the moment you navigate.
Sanctum does not read the contents of any page. It declares no content scripts, holds no scripting permission, and requests no host permissions, so it has no ability to inject code into the sites you visit or to see what is on them. Sub-resources are blocked through Chrome's declarative rules API, which means the browser evaluates the rules and Sanctum is never handed the requests at all.
What it sends
Nothing. The extension package contains no
fetch, no XMLHttpRequest, no
WebSocket, and no sendBeacon. There is no code
path capable of transmitting anything, which is a stronger guarantee
than a promise not to.
Sharing and sale
No data is sold, transferred to third parties, or used for any purpose beyond making the extension work on your own machine.
Permissions
declarativeNetRequest- Performs the blocking. Rules are evaluated by the browser; Sanctum never sees the requests.
storage- Saves your list, your timer and your counters, locally.
webNavigation- Reads the hostname of a page you open, to check it against your list.
tabs- Sends a blocked tab to the blocked page, and re-checks open tabs when you turn blocking back on.
alarms- Fires once when a focus session ends.
offscreen- Plays the end-of-session chime; a service worker has no audio of its own.
Sanctum requests no host permissions at all.
Changes
If this policy changes, the updated version will be published at this address and the date at the top will change. Since Sanctum collects nothing, any change would be a clarification rather than a new use of your data.
Contact
Sanctum is a browser extension that blocks every website except the ones you allow. This policy covers the extension and nothing else.