I built a CLI tool for Bitcoin cold wallets & offline transaction signing — fully open source, no network access

• GitHub: https://github.com/Drincann/bitcold
• Website: https://bitcold.dev
• npm: https://www.npmjs.com/package/bitcold
• License: WTFPL

Try it without installing: visit bitcold.dev and click the terminal — it connects you to a sandboxed Linux shell with bitcold pre-installed.

As a developer who holds Bitcoin, I spent a lot of time looking for a lightweight, auditable tool for cold storage that I could run on an air-gapped machine. GUI wallets felt opaque, hardware wallets require trusting vendor firmware, and other CLI tools were either abandoned or didn't follow modern BIP standards. So I built my own.

bitcold is an open-source CLI for generating BIP39 mnemonics, deriving BIP84 native SegWit addresses, and signing transactions — all completely offline. No network requests, no external APIs, no telemetry. Just your keys on your air-gapped machine.

Features:

• BIP39 mnemonic generation (12–24 words), or supply your own entropy (e.g. from dice rolls)
• BIP84 native SegWit (bc1...) address derivation
• HD wallet with multi-account support
• Offline transaction signing with QR code output (rendered in terminal, no GUI needed)
• AES-256-GCM encrypted storage with scrypt KDF
• Mainnet / Testnet / Regtest address support

Quick start:

npm install -g bitcold bitcold wallet create my-wallet bitcold wallet receive my-wallet@account_0 

The project is early stage so APIs may still change. Feedback, code audits, and contributions are all welcome.