Definition
SeedSigner is an open-source project that provides firmware and assembly instructions for building a do-it-yourself, air-gapped Bitcoin signing device from inexpensive, off-the-shelf components. A typical build uses a Raspberry Pi Zero (a version without WiFi or Bluetooth), a small LCD, and a camera module. Because the assembled device has no wireless radios and no persistent storage of keys, it communicates with wallet software exclusively by scanning and displaying QR codes.
Stateless design
SeedSigner is described as stateless, meaning it does not retain the wallet seed when powered off. The user re-enters or scans the seed (often as a SeedQR) at the start of each session, signs the transaction, and the private data is cleared from memory when the device loses power. This trades the convenience of persistent storage for a design where a stolen device holds no secrets.
Open-source status and use
The firmware is published openly on GitHub under the SeedSigner organization, and the project explicitly targets lowering the cost and complexity of multisig setups, where several independent signers each control one key. It interoperates with coordinators such as Sparrow, Specter, and Nunchuk over QR-encoded PSBTs.
For related topics, see air-gapped signing and multisig.
In Simple Terms
SeedSigner is an open-source project that provides firmware and assembly instructions for building a do-it-yourself, air-gapped Bitcoin signing device from inexpensive, off-the-shelf components. A typical…