Frequently asked questions

No. Krotze works without registration, e-mail or phone number. You pick a username, and the key that proves it is yours is stored only in your browser. Export your identity from your profile if you want to keep it — otherwise clearing your browser data means your chats are gone, with no recovery.

Scan the channel's QR code (use the “Scan QR” item in the app, or your phone camera). In most channels the owner must approve you; channels with “open join” enabled let you in immediately. Other members see you under your username.

Yes. Open Profile → My devices on a device you are already signed in on, register the new device with the pairing code it shows, and both use the same identity. Each device gets its own key, and you can remove any of them later.

Open Profile and use “Swap my token”. That creates a new token, signs out every other device and invalidates every exported identity file. Your username, channels and messages stay exactly as they are.

Private 1:1 conversations are: text messages are encrypted on your device, with the key wrapped for each participant device, and the server only ever stores the sealed envelope — it cannot read what you write. A device you pair later cannot read messages sent before it existed; that is by design, not a bug. Group channels are encrypted at rest on the server but not end to end. One honest limit of any web app: the server delivers the JavaScript that does the encrypting, so this protects your messages against database access and data requests — not against a malicious operator.

As channel owner, open the channel menu and show or download the QR code. Anyone who scans it can apply for membership — you approve or deny every request, unless you enabled “open join” in the channel settings (then everyone with the link joins instantly).

Yes. Enable “open join” for your channel, then pick “Embed on a website” in the channel menu and paste the iframe snippet into your site. Visitors choose a username and chat right away. Uploads are switched off by default in open channels, and joining and posting are rate-limited to prevent flooding.

Every channel deletes itself — all messages, media, members and meta information — after a period of inactivity. Default is 7 days; the owner can set 1 to 365 days.

Yes. You can delete individual messages, wipe your data when leaving a channel, or delete everything you ever posted with one button in the app settings. Channel owners can additionally destroy an entire channel for everybody.

Images (shown as thumbnails with a lightbox), audio (mini player), video (mini player) and zip archives (download link). Any member can remove a shared file.

Tap a member's name in a channel to request a 1:1 chat. The other person must accept. Both sides can destroy the conversation at any time, deleting it for both.

Open krotze.com in your browser and choose “Add to Home Screen” (iOS Safari) or “Install app” (Android Chrome / desktop). Krotze is a PWA — it works like a native app, including notifications.

Yes. Under “Servers” in the app, add any other Krotze server by its address — or scan or paste an invite link from that server, and the app offers to add it. You get a separate identity and username on each server; nothing is shared between them. Channels from every server appear in one list, each with a coloured tag showing where it lives, and you can give every server a nickname and a colour of your own. Unread chats always sit on top.

Yes. A browser can hold only one push subscription, bound to the site you installed Krotze from — your home server. The other servers therefore hand their notifications to your home server, which forwards them to your device. It sees only what the other server puts in the notification (a title and a preview, or just “new message” if you hide message text), never your identity or messages there. A server running an older Krotze cannot relay; you still get its notifications while the app is open.