AirWallet

A free wallet for Bitcoin, Ethereum, Solana, Monero and Zcash that keeps your keys on a device that never goes online and signs by QR code.

#An old phone, a camera, and a payment

The first time you watch it work, it looks almost too simple. Your laptop shows a square of dots. An old phone, sitting in airplane mode with every radio off, points its camera at the laptop's screen, shows you who gets how much and what the fee is, and, once you tap Sign, puts up a square of dots of its own. The laptop reads that one back and sends the payment.

That old phone holds your keys, and it never connects to anything again: no Wi-Fi, no Bluetooth, no cable. The only thing that ever crosses between your two devices is a QR code you can see on a screen. A hacked laptop can show you a wrong payment, but it can't sign one, and the phone that can sign shows you exactly what it's about to do first. That's the whole idea, and the rest of these docs are about making it comfortable to live with.

#At a glance

• Coins: Bitcoin; Ethereum and seven more EVM networks (Base, Arbitrum, Optimism, Polygon, BNB Chain, Avalanche, Robinhood Chain); Solana; Monero; Zcash.
• Platforms: macOS (Apple Silicon and Intel), Windows, Linux, Android, and a Chrome extension. There's also a watch-only web version at airwallet.tech/online.
• Price: free.

#One app, two jobs

There's one AirWallet app per platform. On its first screen you choose how this device is used:

• Everyday wallet: online. It shows balances, receives, sends and swaps, and prepares payments for an offline device to sign.
• Offline signer: for a spare phone or laptop that never goes online again. It keeps the keys and signs by QR code, and AirWallet makes no connection in this mode.

You can switch later in Settings. For the offline device there's also AirWallet Offline, a hardened build that can't connect at all: on Android it doesn't even have the internet permission.

You don't need two devices to start. The everyday wallet works on its own, keys and all, and you can add an offline device whenever you're ready.

#What makes it different

• Keys on a device that never goes online. They're made there and stay there. Your everyday device only watches the wallet: it sees balances and prepares payments, but it can't spend.
• Everything is checked on the offline screen. The signer shows the recipient, the amount and the fee as it reads them from the very transaction it signs, and it refuses what it can't show you completely. There's one case it can't check, which it says plainly before you sign: approving a Squads (Solana multisig) proposal that someone else made.
• Hardware you already own. A spare phone or laptop is enough. Nothing to order, nothing in the mail.
• Free.

#Where to go next

• Why two devices: what the air gap protects you from, and what it doesn't.
• Install: every platform, and how to check your download.
• Your first offline payment: the whole loop, step by step.
• Security model: the details.