Crater privacy policy

Last updated: 2026-10-22

Crater is a Chrome extension that builds a database of Bandcamp fans and their collections, then uses it to suggest music (Also bought, Crate mates, For you). This policy says what it reads, where that data goes, and how to delete it.

The short version

• Everything Crater collects stays on your computer, in your browser's local storage (IndexedDB and chrome.storage).
• Crater has no server. It does not send data to us or to anyone else.
• There are no analytics, telemetry, crash reporting, ads or trackers.
• Its only network traffic goes to Bandcamp, and is the same kind of request Bandcamp's own pages make.
• You can delete everything at any time (see "Deleting your data").

What Crater reads from Bandcamp

Crater only runs on bandcamp.com and its subdomains.

• The page you are viewing. On Bandcamp pages the extension reads the page's own data: the release you are looking at (title, artist, label, tags, id), and who is logged in (your Bandcamp fan id and username), so it can tell which collection is yours.
• Public data about other fans and releases. To find the people who bought a release, and what else they bought, Crater requests public Bandcamp data: a release's list of supporters, each supporter's public collection and wishlist, and the release pages themselves. For each fan it stores their fan id, username, display name, avatar id and the items in their public collection. These requests are sent without your login where Bandcamp doesn't need it (release pages).
• Releases of the artists and labels you follow. About once a week Crater requests each followed account's public list of releases, and the page address of recent ones, from Bandcamp, without your login. It stores them with when it first saw each one.
• Your own collection and wishlist. To sync your own collection, Crater's background service worker calls Bandcamp's collection API with your Bandcamp session cookies (the browser attaches them, as it does for Bandcamp's own pages). This lets it read a wishlist you've set to private. The cookies are sent only to bandcamp.com. Crater cannot read their values and does not store them.

The same session cookies are attached to the requests that read other fans' public collections. They go to Bandcamp only, as with any Bandcamp page.

Crater does not read your payment details, email address, messages or anything else on Bandcamp, and never changes your Bandcamp account.

What is stored, and where

Everything below is stored locally on your device:

• Scanned fans and their collections, release and supporter lists, the recommendation index and the crate-mate leaderboard.
• Your own synced collection and wishlist, your Bandcamp fan id and username, and the time of your last sync.
• Your tags. They never leave the device; exporting them or a CSV is a file you save yourself.
• Releases you hid, and the scan queue.
• Releases of the accounts you follow, when each account was last checked, and the accounts you muted there.
• Your settings, plus the scanner's pacing state (back-off, daily request count) and small interface preferences, in chrome.storage.local.
• When you last opened New from your follows and when Crater last notified you, in chrome.storage.local.
• A short-lived list of release pages open in tabs, in chrome.storage.session (cleared when the browser closes).

All recommendations are computed on your device from this data.

What is sent to third parties

Nothing. Crater does not transmit stored data anywhere. Cover art and avatars are loaded from Bandcamp's image servers (bcbits.com), and the optional preview player is Bandcamp's own embedded player. Both are loaded by your browser from Bandcamp, as on Bandcamp itself.

We do not sell, share or use your data for advertising or credit decisions, and we do not use it for anything other than the extension's single purpose.

Notifications

If you turn on Notify me about new releases in the popup, Chrome asks you to allow Crater's optional notifications permission. With it, Crater shows a desktop notification when its weekly check finds new releases from the artists and labels you follow. The notification is made on your device from the data above; nothing is sent anywhere. It's off by default, and turning it off stops it.

Deleting your data

• Clear all data: open the Crater popup and use Clear all data. It deletes scanned fans and collections, your synced collection, crate mates, hidden releases and the scan queue. Your settings are kept.
• Uninstall: removing the extension from chrome://extensions deletes all of its stored data, including settings.

Because the data never leaves your device, we can't see it and have nothing to delete on our side.

Children

Crater is not directed at children.

Changes

If this policy changes, the new version will be published at the same address with a new date.

Contact

st.nuriar@gmail.com