What it does
AirGap pairs a Vault application for secret keys with a companion Wallet that handles network activity. Its free apps can run on separate phones with QR communication or together on one phone. A dedicated offline device is needed for the separated cold-wallet arrangement, not for all AirGap use.
AirGap gives Vault and Wallet different jobs. In the two-device setup, Vault runs on the offline phone and retains the secret material. Wallet runs on the connected device and prepares transactions. The secret belongs in Vault, while the companion uses public account information.
Sign with QR codes
Wallet prepares an unsigned transaction and shows a QR code. Vault scans it, displays the request and signs after approval. Wallet then scans the signed response and broadcasts it. The two scans move transaction information between the devices without turning the offline phone into the network-facing wallet.
The same-device route switches between the two apps instead: Wallet prepares the request, Vault opens for signing, and Wallet receives the result for confirmation and broadcast. That arrangement is supported, but it does not provide the physical separation of an offline phone.
Distinguish recovery material from a device unlock
Retain the 24-word secret and any optional BIP39 passphrase used with it. Android's Recovery Key can unlock an encrypted backup associated with the original device; it is not a replacement for the seed if that phone is lost.
The apps are free and the local setup does not require a service account. Optional hardware and metal-backup accessories are separate purchases. Supported third-party wallet integrations have their own asset and service conditions, so an integration should be checked for the intended signing task.
Strengths
- Compatible wallet integrations can use Vault as the signer
- A same-device option is available before committing a separate offline phone
Watch out for
- The cold-wallet arrangement requires a dedicated offline device
- An Android Recovery Key does not replace the secret needed after device loss
- Supported assets and signing methods depend on the selected integration
Best for
- People using a spare phone as an offline crypto signer
- Users comparing separate-device QR signing with a same-phone app workflow
Sources
- AirGap Vault, Wallet and integrations (Oct 27, 2026)
- AirGap on a single device (Oct 27, 2026)
- AirGap Vault setup (Oct 27, 2026)
- AirGap cost, recovery and compatibility FAQ (Oct 27, 2026)