Launching today
BitTool Signer
Turn a spare phone into an offline crypto signer
3 followers
Turn a spare phone into an offline crypto signer
3 followers
Turn a spare phone into an offline transaction signer. BitTool Signer keeps keys on the offline device and exchanges signing requests and signatures by QR. Supports Bitcoin, EVM, Solana and TRON, with public source and a separate online companion.
Free
Launch Team
Framer AI AgentsDesign and publish professional sites with AI
Promoted
Hi Product Hunt — I'm Tom, building BitTool Signer.
BitTool Signer is an offline transaction-signing app for iOS and Android. A dedicated offline phone holds the keys and reviews signing requests; QR codes carry requests and signatures between it and an online companion, which prepares and broadcasts transactions. It supports Bitcoin PSBT, EVM transactions, Solana and TRON.
The iOS source is MIT-licensed, and the Android source is public. Build instructions, tests and compatibility limits are available in the repositories. Public security reviews are AI-assisted and include disclosed findings; we have not claimed an independent third-party audit.
I'd welcome feedback on the setup flow, transaction review, QR interoperability and build reproducibility.
Product and downloads: https://bittool.com/signer/
iOS source: https://github.com/bitbill/bitto...
Android source: https://github.com/bitbill/bitto...