AirLink
Messages and calls without the internet.
Talk to the people around you when the network is gone. AirLink carries sealed text and live voice between nearby devices over Bluetooth Low Energy and peer-to-peer Wi-Fi at the same time, relaying through other AirLink devices when it has to. No SIM, no data plan, no account.
Free. macOS 14 or later, Apple silicon or Intel. Unzip AirLink.zip and drag AirLink into Applications. Release notes
How it works
Step 1
Find
Devices discover each other over Bluetooth LE and peer-to-peer Wi-Fi. Every device is both client and host, so nobody has to go first.
Step 2
Seal
Each message is encrypted to the recipient with HPKE, sender hidden inside the ciphertext. Calls get fresh keys every time.
Step 3
Keep talking
Messages relay through other AirLink devices, and the sender keeps retrying for someone out of range. Voice goes down two roads at once.
At a glance
- Transports
- Bluetooth Low Energy and peer-to-peer Wi-Fi, used together. Direct UDP for live voice.
- Mesh
- Flooding with a hop limit of 5 to 8 set by crowd size, and duplicate suppression. Delivered in 34 ms at one hop and 102 ms at two, median, in a measured session.
- Encryption
- HPKE (X25519, HKDF-SHA256, ChaCha20-Poly1305) for text, with the Ed25519 sender signature inside the ciphertext; fresh X25519 keys for every call; message bodies encrypted on disk.
- Voice
- Opus, 24 kHz mono, 20 ms frames, 24 kbit/s, sent over the mesh and a direct Wi-Fi path at once.
- Identity
- No phone number, no sign-up. A short call ID like A3F9-K2P1 derived from your keys.
- Platforms
- macOS 14 or later, on Apple silicon or Intel, available now. iOS 18 to follow. Becoming part of Kalon after Air Kalon.
Questions
Asked, answered.
- Does it work with no Wi-Fi at all?
- It is built to. Bluetooth Low Energy carries text and voice between nearby devices, and peer-to-peer Wi-Fi is used as well when both devices have it, without a router or hotspot. Our published measurements so far were taken with Wi-Fi available.
- Do I need an account?
- No. AirLink has no sign-up, no phone number, and no server anywhere. Your identity is a pair of keys generated on your device, shown as a short call ID.
- Can someone in the middle read my messages?
- No. Messages are sealed to the recipient with HPKE, and the sender's signature travels inside the ciphertext. Relaying devices can see which key a packet is addressed to, its type and its size, but not what it says or who sent it.
- When can I try it?
- Now, on a Mac. Download AirLink at the top of this page: it needs macOS 14 or later, on Apple silicon or Intel, and keeps itself up to date. The iPhone app is not out yet; tell us on the contact page and we will let you know first.
Intelligence on the device you already own.
Private by default, fast without a network, and free for macOS and iPhone.