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A crypto wallet, such as MetaMask, Coinbase Wallet, Rainbow or any wallet that supports WalletConnect. That's your account: no email, phone number or password.

The first time you use Chainmail on a device, your wallet signs a message that proves the new messaging keys belong to you. It's free and isn't a transaction. You won't be asked again on that device.

Tap the pencil icon and enter a wallet address or ENS name (like jack.eth). The other person needs to have used Chainmail (or another XMTP app) once, so their wallet can receive messages.

To let people reach you, share your address: the QR-code icon above your chats gives you a QR code and an invite link.

Yes. Open Chainmail in your wallet app's built-in browser (for example MetaMask → Browser), or in Safari or Chrome and connect your wallet with WalletConnect. Add it to your home screen for an app icon.

Your messages are private, but your wallet address isn't: it's how people reach you. Anyone who knows an address can look up its balance and every past payment on the blockchain, as with any wallet.

If you'd rather keep your main wallet to yourself, connect a separate wallet just for chatting, and keep only small amounts in it. You can move money to it whenever you need to pay someone.

Chats from new people arrive as requests. You can read them, but they don't get read receipts until you tap Accept. If something looks wrong, tap Block.

Never pay, sign or approve anything because a stranger asked you to.

That wallet's address starts and ends like someone you know, but it's a different wallet. Scammers create lookalike addresses because people only check the ends. Don't send it money unless you've checked the whole address with the real person.

Each browser or app you use Chainmail on gets its own keys, which can read your new messages. Chainmail only adds one when you sign a request inside the Chainmail app itself. It will never ask you to sign anything on another website, in an email, or in a message.

If you see this warning and you didn't just sign in somewhere new, someone may have tricked you into signing for them. Tap Open Devices and remove any device you don't recognise. If it was you, tap It was me.

Never. Nobody legitimate will. Anyone who has your recovery phrase can take everything in your wallet. If you've shared it, move your funds to a new wallet straight away.

In a chat, tap the coin icon, choose USDC or ETH, enter an amount and confirm in your wallet. Your wallet shows the exact fee first. A card appears in the chat and turns to Confirmed when the payment lands.

In a 1:1 chat, the coin icon has a Request option: the other person gets a card with a Pay button.

In a group, the coin icon opens Split a bill: everyone ticked gets a request for their share, and one card shows who's paid.

Not yet. Payments currently use Base Sepolia, a test network with free test money. Cards say “Test network” while that's the case.

Blockchain payments can't be reversed by anyone, including us. That's why Chainmail asks you to confirm the address before your first payment to any wallet.

Only the people in the chat. Messages are end-to-end encrypted on your device with XMTP. Chainmail has no server that receives them.

Each device has its own encryption keys, so a new device starts empty. Go to Settings → History:

• Transfer: open Chainmail on a device that has your chats, then press “Get history from my other device” on the new one.
• Backup file: download an encrypted backup with a passphrase, and restore it on the new device.

Messaging runs in one tab at a time so your chats stay consistent. Press Use here to move it to this tab.

Settings → Devices lists every browser that has your keys. Remove the lost one so it can't read new messages.