Help & FAQ
Everything about your account, encryption, calls and privacy — in one place.
Installation
On Ubuntu, Debian and Mint, download the .deb from the download page, double-click the file and click Install. For other distributions there is an AppImage: it needs the libfuse2 package and permission to run.
Run the commands below in a terminal opened in the folder with the downloaded file (usually Downloads). The same .deb:
sudo apt update sudo apt install ./Calmis-*-linux-amd64.deb
Or with dpkg. It does not pull in dependencies by itself, so if it complains about missing packages, run the second command right after:
sudo dpkg -i Calmis-*-linux-amd64.deb sudo apt-get install -f
AppImage on Ubuntu 22.04 and Debian 12 (on Ubuntu 24.04 the package is called libfuse2t64; on Fedora it is fuse-libs, on Arch fuse2):
sudo apt update sudo apt install libfuse2 chmod +x Calmis-*.AppImage ./Calmis-*.AppImage
If you would rather not install libfuse2, the AppImage also runs without it:
./Calmis-*.AppImage --appimage-extract-and-run
In this mode the AppImage unpacks itself into a temporary folder (a few hundred megabytes) on every launch and takes a few seconds longer to start. The folder is removed when you quit; nothing stays on the system. It is a fallback: for everyday use install libfuse2 or take the .deb.
Almost certainly the libfuse2 package is missing: Ubuntu 22.04 and later do not ship it, and the AppImage silently fails to start without it. Install libfuse2 (libfuse2t64 on Ubuntu 24.04) and allow the file to run; the commands are in the question above. On Ubuntu, Debian and Mint the easiest route is the .deb: it installs with a double-click.
Account management
Download Calmis for iOS or Android and tap “Create account”. You'll be asked for an invite code first — without one, registration won't go through. After that you only need a username and a password: we don't ask for a phone number or an e-mail.
From someone who already uses Calmis: everyone has their own supply of codes.
In the app settings, in the invites section. Next to each code you can see whether it has been used or is still free. The supply is limited, so hand them out wisely.
A username is 5 to 32 characters: Latin letters, digits and underscores. It is unique and can be changed no more than once every 30 days.
Tap “Forgot password” on the sign-in screen and enter your recovery key. We don't ask for an e-mail or a phone number, so the key is the only way back in — keep it somewhere safe.
Yes. On the sign-in screen tap “Other server” and enter the address. Some Calmis features (P2P, security settings) work only on Calmis servers. And no, it's not on purpose. It's just the only way we can promise the best of Calmis.
Settings → Account → Delete account. This permanently removes your profile, chats and keys — it cannot be undone.
Chats
Folders group chats by topic. Create them in Settings → Folders and add chats to them.
A spoiler hides part of a message behind a blur until the reader taps it. Select the text and choose “Spoiler” in the formatting menu.
Tap the attachment icon in any chat. Files up to 300 MB each are supported.
Only if history visibility is turned on for that chat. By default new members see messages from the moment they join.
Tap the search icon at the top of a chat, or use global search on the home screen to search across all your chats.
End-to-end encryption
Messages are encrypted on your device and can be read only by the people in the chat — not by Calmis and not by anyone in between.
Only the people in the chat. Encryption keys never leave your devices.
A recovery key is a code that restores access to your encrypted messages if you have signed out everywhere. Save it somewhere safe.
Key storage is an encrypted copy of your chat keys stored on the server. It can be opened only with your recovery key.
If both the recovery key and all your active devices are gone, access to the older encrypted messages cannot be restored — that is the price of privacy.
Every sign-in to Calmis creates a separate device with its own keys. Messages are encrypted for all of the other person's verified devices.
Sign in on another device and end the lost session. Messages stay end-to-end encrypted.
It means the contact's keys have changed — a new device or a reinstall. Verify them again to be sure it is really them.
Calls
Open a chat and tap the call icon at the top, or pick a contact and tap “Call”. Audio and video calls are both available.
Yes, both one-to-one and group calls are protected by end-to-end encryption.
Usually a weak or unstable connection. Try Wi-Fi or switch networks.
Yes. Calmis connects directly and switches to fallback routes when the network is restricted, so in most cases a VPN isn't needed.
P2P mode
In P2P mode media and calls connect your devices directly, without relaying through a server — for extra privacy.
Through a server, data travels across the Calmis infrastructure. In P2P the devices connect directly — fewer intermediaries and lower latency.
A direct connection can't be established, so the message arrives later — when the other person comes online, or through the server if your settings allow it.
Yes. Calmis has no plans or paid tiers — P2P mode is available to everyone as an experimental feature, with no limits.
Privacy & data
Only what the account needs to work. Message content is end-to-end encrypted and unavailable to us.
No. Messages are end-to-end encrypted and the keys live only on your devices — Calmis has no access to the content. That is a condition of our privacy architecture.
In the chat or the profile, tap “…” → “Report”. We will look into it; the end-to-end encryption of other conversations is not affected.
Together with your account: Settings → Account → Delete account. Your profile, chats and keys are erased permanently.
Bugs & Feedback
Settings → Help → Report a problem. Or shake your device — a screenshot will be attached to the report automatically.
Send your ideas through Settings → Help → Send feedback. We read every message.
Write to support@calmis.io with a description and steps to reproduce. Please don't publish the vulnerability before a fix is released.