A call is encrypted end to end between the two phones. Nobody in between can hear it, and nobody in between can watch it.
While a call is connecting the screen says Verifying. During those moments CHANNEL is checking that the phone answering is really the one you called, by comparing the key it presents against the one that arrived inside the sealed invitation.
You hear nothing until that check passes. That is deliberate: a call that could be listened to should never reach your ear first and be questioned afterwards. When it passes, the line reads Encrypted end to end and the other person becomes audible.
If it fails, the call ends and the conversation records that it failed.
While it checks, the seconds count beside Connecting and a line under Verifying says the call ends on its own if the check cannot be completed. If that happens, the screen says so rather than just ending.
Open a conversation and tap the phone at the top. Every call starts as a call; video is a button inside it, and either of you can press it at any time.
While the other phone rings, you hear a ringing tone, the way an ordinary phone call sounds, until they answer or the call ends. On Android in silent mode it plays at the earpiece or headphones and not on the loudspeaker.
You can also call without opening a conversation. The phone icon on the conversation list opens a screen of names: Favourites first, then the people you call most, then everybody, alphabetically. Press and hold a name to make it a favourite.
If nobody answers, the conversation offers Record voice message for two minutes, so you can leave a voice message instead.
Calling each other at the same moment. If the two of you call each other within moments of each other, the phones settle on one call rather than ringing each other forever: whichever side gives way joins the call that is already under way instead of ringing. Pressing Call while that person's call to you is already ringing answers it.
On iPhone, if the system ends a call before it begins, which a Focus, a Screen Time limit or another call can do, CHANNEL says Call did not start, and the conversation shows the same line.
In a group conversation of up to eight people, the phone at the top rings everybody in it at once. Each person answers or declines on their own, and the call carries on between whoever is on it; one person hanging up leaves the others connected.
With four people or fewer, each of you can turn a camera on. A larger group call is voice only.
Every person on the call is connected to every other, sealed exactly like a call between two, so you are connected to the members you have linked with. Somebody in the group you have not linked with is not part of your side of the call.
On the Calls page, the menu at the top has New Call Link. It makes a link and opens the share sheet with a sentence around it, so you can send it in any app.
When somebody taps it on a phone with CHANNEL, the app opens and asks Call <name>? before dialling, so a link tapped by mistake does not start a call on its own. Confirming calls you. If the two of you are not linked, the phones link first, exactly as they do from an invitation link, and the call follows. On a phone without CHANNEL, the link opens a page on channelmessenger.net that says who is calling and how to get the app; the call itself is made in the app, never in a browser. If your device does not answer in time, their screen says so, and tapping the link again tries again.
Anyone who has the link can use it, including somebody it was forwarded to. So it works once and only for 24 hours, and you see who is calling before you answer.
Somebody you have not paired with yet cannot be rung the ordinary way, because there is nothing yet to seal a call to. On their card, the call button offers Ask to call on CHANNEL instead, at a number, address or handle they publish.
Their phone rings, showing your name under Not in your contacts. Your own screen says Ringing, with Cancel. The call connects the moment they answer, exactly like an ordinary call — answering is the same as accepting a message from you. If they decline, or do not answer, nothing else happens; the conversation then offers Record voice message, as it does after any unanswered call.
Settings › Calls › Calls From People Not in Your Contacts lets somebody reach you this way too — anybody who has your number, address or handle can ring this device even though you have no contact card for them yet. The screen shows the name they give, under Not in your contacts.
Answering accepts them. It runs the same exchange as accepting a first message: a contact card is created and the call connects. Declining, or not answering, only adds a line to the Calls tab — nothing else happens, and nothing is left waiting for a decision.
A call that arrives from somebody who is not a contact does not ring when it names one of your contacts, by their key or by the name it claims; it waits in the requests list instead.
If you do not answer, they can leave one voice message. Long press the line under Not in your contacts for Play Voice Message and Accept; playing it does not add them, and accepting it does, the same as answering the call would have.
For our server to ring this device at a value you publish, it keeps a way to wake this device alongside that value, for as long as the value stays published.
The phone rings. On the lock screen it names the caller only when Calls on Lock Screen is on or the caller's page says Show; otherwise it says CHANNEL. Answer or decline from the ringing screen, or from the lock screen.
Declining from the lock screen before the call has fully arrived declines it. On a Mac there is no system call screen, so an incoming call rings through a notification with sound.
On Android, where the call is answered depends on where you are. With CHANNEL on screen the incoming call is the call screen, and its green button is the answer; the entry in the notification shade carries no buttons, because the screen in front of you already has them. With CHANNEL in the background or the phone locked, the notification carries buttons to answer and to decline, because there it is the only way in. Those two words come from Android itself rather than from CHANNEL, so they appear in whatever the phone's own language is.
A call rings a phone that is locked or in a pocket. It is announced by a push. With Only When I Check chosen under Waking your device, nothing is registered with Apple or Google, so a call rings only while CHANNEL is open, and otherwise appears afterwards as a missed call.
After a phone restarts, a call rings only once the phone has been unlocked. Until that first unlock the phone keeps CHANNEL's keys and messages locked away, from CHANNEL too. On iPhone a call in that time is turned away at once; on Android it waits for the unlock. Either way it appears in the conversation as a missed call when you unlock.
A call that arrives after the caller has given up does not ring either. It is written into the conversation as a missed call, at the time it was made, rather than ringing for a call nobody is waiting on.
Every device of a shared profile rings. When your profile is on more than one device, a call to you rings each of them; the first one you answer on has the call, and the others stop ringing and say it was answered on another device. A call you make from any of them is answered on that device.
When you call somebody who has several devices and one declines, the others keep ringing. The call ends when every device has declined, or when 45 seconds have run out.
Answering asks for the microphone the first time, the way placing a call does. On Android, if the phone has been told never to allow it, tapping Answer says so and offers Open Settings or Decline — a call is never answered in silence.
Tap the minimise button at the top left. The call keeps running and you are back in the conversation, so you can read something out, check a number, or show a picture. The conversation button at the top right opens this person's conversation from wherever you answered, with the call still running, and the green bar takes you back.
A green bar across the top of every screen says the call is live and how long it has run. Tap it to go back.
The screen stays on while a call is connected, even away from the call screen — sending a photo or reading the rest of the conversation does not let it go dark.
When a call you placed does not connect, because it fails, nobody answers, it is declined, or the person is on another call, the screen stays and says what happened. Cancel closes it, Message opens the conversation, Voice message opens it and starts recording at once, and Call again places the call again.
Leaving CHANNEL during a video call — the home gesture, or switching to another app — floats the other person's picture in a small window over whatever you do next, and the call keeps running behind it. Tapping the floating window brings back the full call screen. It floats only while there is a picture to show, so an audio call is unaffected, and ending the call closes it. Settings › Calls › Show the Call Outside the App turns this on or off. It is on unless you turn it off; with it off, the video pauses until you return. It applies only while the call has video, and it never ends, pauses or mutes the call itself.
The person's name sits at the top with the length of the call counting up under it, and one row of buttons sits at the bottom: Video, Speaker, Mute and End call. A button that is on is white: Speaker when the sound is on the loudspeaker, Mute when your microphone is off, Video when your camera is on.
When somebody calls while you are on a call, their name appears over the call with three choices.
The call on hold shows Swap, which brings it back and puts the other one on hold. Ending the call you are on brings the held call back. Ending the held call leaves the one you are on. A call on hold with nothing else live shows Resume.
When both people are in a group with you, the call on hold also shows Merge, which turns the two calls into one group call of the three of you. Each of them is rung again and joins by answering; the group call carries the group's name, and nobody else in the group is called. Merge is on CHANNEL's own call screen.
Add Person, at the top right of the call screen, lets you pick a contact to add to a connected call. When you, the person on the call and the person you pick are all in one group, the call becomes a group call of the three of you: the person you pick is rung, the person you were talking to is rung again and joins by answering, and nobody else in the group is called. When the three of you are not all in one group, the screen says so and the call carries on. Add Person is on CHANNEL's own call screen.
One call is live and one is waiting or on hold, counting every profile on the phone. A third caller hears that you are on another call. On an iPhone the same choices appear on the lock screen and in the system's call banner.
Settings › Calls › Reduce Background Noise filters steady sound, such as traffic or a fan, out of your voice on calls. It is on unless you turn it off, and a change applies from the next call. Echo cancellation and level control are always on.
Afterwards the conversation shows a line: Voice call ยท 4:07, or Missed call if it was not answered.
A connected call's line ends with a letter for how it connected: L for your local network, 6 for a direct connection over IPv6, I for a direct connection over the internet, or T for our relay — the same letters the Calls tab shows beside every call. A call that never connected carries no letter.
It is not written to your phone's call history. That history is backed up and readable by any app allowed to see your calls, so CHANNEL keeps its own record in the conversation instead, on this device, sealed like everything else there. You do not lose the history; you lose the copy you do not control.
The Calls tab lists every call in one place, newest first. Tap one for Call, which calls that person again (turn on video once the call is up), or Message, which opens the conversation ready to type. At the top, Call opens the list of people to call, the people you have marked as favourites are one tap away, and Favorites is where you mark them. The i on a row shows what is known about that call. With no calls yet, the page says No calls yet and offers Call, which opens the same list of people to call.
Long press a call for the same Call, and two more things. Info shows who it was with, which way it went, whether either of you showed video, when it started, when it ended, how many seconds of media flowed, and why it stopped. When the call connected it also names how it connected: your local network, straight to their phone over IPv6, straight to their phone over the internet, or through our relay. Delete removes that one line.
A call that never connected has no end time and no route, and those rows are absent rather than filled in with a guess.
On a wide window, Favorites is a section of its own above Recent — the people you have marked, or, with none marked, the three you call most — and beside the list are three large buttons: Start Call opens the list of people to call, New Call Link makes a call link, and Call a Number opens New Message, where you type a number or an @handle.
A call goes directly between the two phones wherever they can reach each other, and nothing about it touches our server.
Where they cannot reach each other directly, the call is carried by a relay. The relay passes the stream along and cannot hear or watch it, but it sees when the stream starts and stops, so it learns that two endpoints were on a call, when, and for how long. CHANNEL asks for that relay's credentials on a schedule of its own, roughly once a day, so placing a call does not usually tell our server anything; when the credentials are due for renewal, placing or answering a call fetches fresh ones first, and our server sees that request at that moment.
If the connection is lost during a call — you walk out of Wi-Fi range, the signal goes — the call ends a short while later and the conversation records that it failed, rather than staying up in silence. A brief blip, a lift or a doorway, does not end it.
Calls over the Internet need a subscription; calls on the same network are free. Without a subscription, a call works when the other phone is on the same Wi-Fi or local network as yours, or connected to it by Wi-Fi Direct: the call then stays on that network, with no relay and nothing sent over the Internet. When that is not the case, Call says "Calls over the Internet need a subscription", with Open Subscription. A call from somebody who could only reach you over the Internet does not ring: it is listed as a missed call, the app says who called and why, and their phone hears an unanswered call, nothing about your subscription. Bluetooth alone cannot carry a call's sound or picture.
Connecting a call directly means each phone learns the other's network address, which is roughly a town and an internet provider. That is a normal part of connecting two devices to each other, and it is the same for every app that carries a call without a server in the middle.
Wi-Fi says more about where you are than mobile data does. On a home or office Wi-Fi, the address the other phone sees belongs to that building's internet line, and looking it up puts you within a neighbourhood of it. On mobile data the address belongs to your carrier, is usually shared by many people, and often appears in a different town altogether. It is also usually the same address from one call to the next, so somebody who notes it once can tell when you are home. So if where you are is sensitive, take the call on mobile data.
Settings › Calls › Use Wi-Fi for Calls turns this off. Calls then prefer mobile data, and a call that has no other way to connect still uses Wi-Fi rather than failing. It is a separate switch from Direct Wi-Fi, which chooses how messages travel between phones that are near each other.
Settings › Calls › Relay Only goes further: every message and every call to that person is carried by our relay, so the other phone never learns this one's address at all, and nothing goes to them by Bluetooth, Direct Wi-Fi or the local network, which would show that you are nearby. It is the protection WhatsApp calls Protect IP address in calls, and here it covers messages as well. It adds a little delay to calls, and it tells the relay that a call happened; the relay still cannot hear or watch it. While no relay is available, messages wait and a call cannot be placed. You can turn it on for one person from their card, which overrides the setting for them. That person cannot tell this device is nearby either: it says nothing they can recognise over Bluetooth or the local network. Other contacts nearby can, while those switches are on; turning them off in Settings › Reach keeps the phone out of sight to everyone.
The buttons beside the CHANNEL call button hand the call to another app — the dialler, FaceTime, WhatsApp, Signal or Telegram — using the numbers and apps on that person's card. Those calls are not CHANNEL calls and nothing about them is protected by CHANNEL.
Messages have the same escape, in two places rather than on this bar: see Writing to somebody who is not on CHANNEL in Messages.
English is the reference text; any translation is a convenience.
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