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.

Those direct links typically cover tens of metres, with range affected by walls and people. A mesh extends the route by asking nearby phones to carry the message onward.

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.

Build on the connections available to you

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 longer hops, optional Meshtastic radios can extend Knit direct messages and the public Nearby room. Put a board with each distant group so nearby phones can share the connection. Group chats and attachments use the phone mesh or optional relays.

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.
The phone mesh needs a chain of nearby Knit devices. Optional Internet relays can carry existing direct and group chats across greater distances.
Knit runs on Android 10 and newer, with iPhone on the way.
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. Install Knit on both phones and enable Bluetooth and Wi-Fi. Nearby Knit phones can carry the conversation directly, with no internet required. Everyone you want to message needs the app.

Does airplane mode stop it working?

You can use Knit in airplane mode by turning Bluetooth and Wi-Fi back on. That keeps the phone mesh available while the cellular radio is off.

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.