Offline guide

How to text when you have no service

Your phone has two radios that don't care whether a network exists. Here's what they can and can't do.

"No service" covers several different problems, and they don't all have the same answer. There is no coverage where you are. There is coverage, but everyone around you is already sitting on it. You have a phone but no SIM, or a SIM that costs a fortune to use in this country. The bars are gone because the power is out.

What they share is that the tower is out of the picture, and almost everything on your phone assumes the tower is there. SMS goes to a cell site. WhatsApp, Signal, iMessage and the rest go to the internet. Take away the infrastructure and they all queue up waiting for it to come back.

What still works when the network doesn't

Your phone has two short-range radios that talk to other devices directly: Bluetooth and Wi-Fi. Neither of them needs a carrier, a router or an account. They are how wireless earbuds work in a tunnel, and how two phones swap a file with no signal on either one.

The catch is that they only reach as far as they reach — tens of metres, less through walls and bodies. Directly, they connect you to whoever is standing near you and nobody else. That is a real limit, and it's the reason a plain Bluetooth chat app has never been much use.

Relaying changes that. If every phone running the same app passes on what it receives, a message doesn't have to cross the whole distance in one jump. It crosses one short hop at a time, through the people in between. Ten phones spread across a field cover far more ground than any one of them can.

How Knit uses that

Knit meshes over Bluetooth LE and Wi-Fi Aware, so a message hops phone to phone until it reaches the person you sent it to. No internet or cell service is required for any of it: there is no server in the path, and no account to make.

When there is no route to someone right now, the message waits rather than failing. It sits in the mesh and moves when a path appears — somebody walks between you, or the person you're messaging comes back within range of anyone who is carrying it.

Direct and group chats are end-to-end encrypted, so the phones relaying for you pass along sealed traffic they can't read. The public Nearby room works differently on purpose: it's an open broadcast, plaintext by design, like talking out loud in a crowd.

The other options, honestly

If you have even one bar, a plain SMS is still the most reliable thing you can send. Texts are tiny and networks prioritise them; a message that won't go through on WhatsApp often goes through as a text. Try that first.

Some recent phones can send emergency messages via satellite with no ground network at all. If your phone has it and you're in real trouble, that is the tool, not a mesh app.

For kilometres of range rather than tens of metres, dedicated LoRa radios like Meshtastic are a different class of device — and a different class of hassle, since everyone you want to reach needs one.

Where this doesn't help

Everyone you want to reach needs the app. A mesh is made of participants; there is no way around that.
It reaches people near you, or near someone near you. It is not a way to message a specific person on the other side of the country.
Knit is Android only, and needs Android 10 or newer.
It is not a way to contact emergency services. If you have any signal at all, an emergency call goes through on any network, including one you have no SIM for.

Common questions

Can two phones text each other with no service at all?

Yes, if both are running an app that talks over Bluetooth or Wi-Fi directly. That's what Knit does. What no app can do is reach a phone that isn't running one — without a network, there is nothing in the middle to deliver to.

Does airplane mode stop it working?

Not by itself. Airplane mode switches off the cellular radio, but you can turn Bluetooth and Wi-Fi back on with it enabled, and that is all Knit uses. It's a reasonable way to save battery when there's no coverage to find anyway.

How far can a message actually travel?

One hop is the range of Bluetooth or Wi-Fi, typically tens of metres. Total distance depends entirely on how many people are in between: through a dense crowd a message can cross a site far larger than any single phone could reach, and across an empty field it goes as far as the last phone and stops.

Does it use my data allowance?

No. The mesh is radio-to-radio and never touches the internet, so there is nothing to bill. The one exception is opt-in: if you switch on Internet relays, an existing chat can keep flowing over the internet when nobody is in radio range, and that uses data like any app.