Questions people ask

Yes, permanently. No price, no subscription, no advertisements, no paid tier, no feature held back for a premium version, and no free trial that ends. The licence makes that a promise rather than a plan: nobody can take it away from you, and nobody can put a price on it.

No. Nor an email address, a username or a password. Your phone or computer generates a cryptographic key the first time you open the app, and that key is your address. You share a 16-character code or a QR, and that is the whole of signing up.

Scan their QR code, or paste or type their 16-character code. Scanning in person is safest, because nothing passes through another app that could alter it on the way. Sending the code through another messenger is fine and convenient. Just compare the four safety words aloud on your first call, which catches the one attack that sending it could allow.

No, and not because we have chosen not to. Messages and calls are encrypted between the two devices with keys that exist only there. When a server is involved at all, it holds bytes sealed to the recipient's key. We could hand over everything we have and it would not contain a sentence of anybody's conversation.

We hand over what we have, which is little: no names, no phone numbers, no contact lists, no message content, and no record of who contacted whom once an item is gone. The directory holds each device's address, public keys and platform, and a phone's push token. While a call invitation or an offline message is waiting (at most 60 seconds for a call invitation, 72 hours for a message) the server does know which two addresses it passes between. The privacy policy lists everything it holds, and for how long.

They are derived from the key the two phones actually agreed on, so both people see the same four words if and only if nobody is sitting in the middle of the call. Read them aloud. If they match, the call really is between the two of you. If they do not, hang up. It is the one check nobody can do for you, and it takes three seconds.

On the same Wi-Fi, yes. Two devices on the same Wi-Fi network or hotspot can hold a full encrypted call with no internet connection and no server: on Android once the phone being called has tapped Ready to receive, on iPhone while Clavenzo is open on it, and on a computer whenever Clavenzo is running. Messages and files travel the same way while the app is open on both. The encryption and the safety words are the same. Beyond the local network, a message waits for a connection.

Speech is coded at 13.2 kbit/s, which is 33 bytes every 20 milliseconds and about what a GSM call uses. The jitter buffer measures the network and adapts to it, and when packets are lost the decoder smooths over the gap instead of clicking. On a good direct connection the app can switch to clearer HD sound.

Calls and messages between devices on the same Wi-Fi do not use them, so those carry on. For everything else your device is registered with every server in the fleet and checks them all, so losing one does not lose you. The list of servers is signed and includes plain addresses with pinned certificates, so a failed name server or content-delivery network does not cut you off either. A message waiting on a server that is down is delivered when it comes back, as long as that is within 72 hours.

Usually, yes. A voice call needs 13.2 kbit/s, about 6 MB an hour, and conceals lost packets instead of breaking up. When two networks will not connect directly, the call goes through an encrypted relay. For networks that force a proxy, or where the name server is blocked, SOCKS5 and HTTP CONNECT are built in. What no app can do is get through a network that blocks every route out. There, calls on the same Wi-Fi are what is left.

That a server is relaying this call rather than the two phones talking directly. It is not a security warning. The call is encrypted end to end either way, and a relay forwards packets it cannot decrypt. It usually means the two networks would not let the phones reach each other, which is common on mobile carriers. The dot is off by default and can be switched on in Settings.

None. No usage events, no screen views, no session recording, no crash reporter, no advertising identifier, no fingerprinting. The only closed-source third-party code in the app is Google's push service on Android, which wakes the phone for calls and messages. This website matches: no fonts, no analytics, no cookies, no trackers from anywhere else.

The clearest difference is identity. Both of those are built on a phone number, which ties your account to a carrier, a legal name and a SIM card somebody else can take over. Clavenzo has no number and no account at all. It also calls directly between devices whenever the network allows, can call over a local Wi-Fi network with no internet, and never uploads your address book. What Signal has that Clavenzo does not: years of independent security audits, a very large user base, group chats, and linked devices that share one account. If you want the most scrutinised tool available, that is a real and honest reason to choose Signal.

Calls are. Every call adds ML-KEM-768 to its key exchange a moment after it connects, when both apps support it, to keep today's recordings unreadable to a quantum computer that does not exist yet. Messages and files are not, yet: they are sealed with RSA and ML-KEM-768 together, but the ML-KEM key is currently derived from the RSA key, so a quantum computer that breaks RSA would open them too. Fixing that is on our list. The identity key that signs things is RSA-2048.

Not yet. The licence's promises (free forever, no advertisements, no tracking) hold either way, and the source may be published in the future. Until then you are trusting a claim you cannot check yourself, and we would rather say so plainly.

No. It is built carefully and tested heavily, and that is not the same thing as an independent security audit. If your threat model is serious, weigh that honestly. We will update this answer the day it changes.

Anyone holding your unlocked phone. Malware on your device, which reads what you type before it is ever encrypted. An observer of your network learning that you use an app, even if not what you said. Someone you talk to repeating what you told them. And it cannot help if you never compare the safety words. Encryption reduces risk; nothing eliminates it.

Almost always the phone has put the app to sleep, and a sleeping app cannot be woken for a call. In your phone's settings, allow Clavenzo to run in the background and turn off battery optimisation for it. Samsung, Xiaomi and Huawei phones are the usual culprits. The app detects this and offers a one-tap fix on the home screen.

One identity lives on one device. A computer running Clavenzo is a device of its own, with its own address: it does not mirror your phone, so people add it as a separate contact. You can move an identity to a new phone or computer with the identity export, which seals the key with a one-time transfer code, but there is no simultaneous multi-device sync. That is a direct consequence of the key living on one device.

The identity is gone unless you exported it first, and nobody can recover it, including us, because we never had it. Export your identity and an encrypted backup before you change or wipe a phone. Both are in Settings, both are protected by your phone's own screen lock, and both are worth doing today rather than when you need them.

No. Calls and conversations are one to one. Groups are hard to do well under this design, and a weak version would be worse than none.

A voice call is about 13.2 kbit/s of audio, roughly 6 megabytes an hour, before packet overhead. That is a fraction of what most calling apps use. Data saver keeps every call at that rate, and Auto HD uses more only when the connection is good and the call is direct. Video uses considerably more and adjusts to the connection.

Eleven: English, Spanish, French, Portuguese, Russian, Hindi, Bengali, Urdu, Arabic, Chinese and Armenian. The app follows your phone's language and lets you override it in Settings. This website is published in all eleven as well, right to left where the language is.

Phones: Android 7.0 and newer, and iPhone with iOS 15 or newer; the Google Play and App Store listings are coming. Computers: Windows 10 and 11, and 64-bit Linux, from the download page; a Mac app is coming. On Linux, video calls and recording voice messages are still to come. A computer has its own address: it does not mirror your phone.

support@clavenzo.com, read by a person. Privacy requests go to privacy@clavenzo.com, security problems to security@clavenzo.com, and reports of abuse to abuse@clavenzo.com or Report and block in the app. We cannot reset an identity, recover a lost key or read anybody's messages, because there is no account to reset and we keep no copy of them.