Description
Coinkite Tapsigner (TAPSIGNER®) is a Bitcoin hardware wallet in a credit card form factor that uses NFC technology for contactless transaction signing. Made by Coinkite — the team behind the renowned COLDCARD hardware wallet — Tapsigner brings hardware wallet security to an affordable, pocket-sized card.
How It Works
- Setup — During first-time use, you provide a 32-byte chain code for entropy, which is combined with secret entropy generated by the card's chip to create the private key using BIP-32 standards.
- Tap to Sign — Open a compatible mobile wallet, tap the card to your NFC-enabled phone, and the transaction is signed securely on the card.
- Private Key Never Leaves — The private key (XPRV) is generated inside the card and never exported. A backup can be created via an encrypted (AES-128-CTR) file.
Security
- On-Card Key Generation — The private key is generated inside the card and cannot be extracted.
- BIP-32 Based — Uses hierarchical deterministic key derivation without BIP-39 seed phrases.
- Encrypted Backup — The XPRV can be backed up encrypted with AES-128-CTR. The 16-byte decryption key is printed on the back of the card.
- RF-Blocking Sleeve Included — Each card comes with a special radio frequency blocking sleeve to prevent unauthorized NFC access when the card is not in use.
- PIN Protection — A user-set PIN code protects access to the card's signing capabilities.
Compatible Wallets
Tapsigner works with several mobile and desktop Bitcoin wallets:
- Nunchuk (Android, iOS, Desktop)
- Cove (Android, iOS)
- Bitcoin Keeper (Android, iOS)
- Sparrow (Desktop)
- Also works via USB NFC card reader with the open-source cktap command-line tool
Key Use Cases
- Mobile Bitcoin Signing — Securely sign transactions from your phone without exposing private keys.
- Multisig Co-Signing — Works as one of multiple signers in multisig wallet setups.
- Lightning Network — Open and close Lightning Network channels via compatible wallets.
- Message Signing — Sign arbitrary messages using the card.
- App Authentication — Can serve as a hardware-based authentication token.
Open Protocol
Tapsigner uses a fully open protocol — all code is publicly available on GitHub. The card's authenticity can be verified by tapping it on any NFC-enabled phone, which opens a verification webpage.
Ideal For
Bitcoin users who want the security of a hardware wallet in a slim, card-sized form factor that fits in a regular wallet — perfect for everyday mobile signing, multisig setups, and as a portable backup signing device.
Highlights
Pros
- Uses an open-source protocol (cktap on GitHub) and works with Nunchuk, Sparrow, Bitcoin Keeper, and Cove wallets, with an SDK for developer integrations.
- Private key is generated inside the secure element and never leaves the card — only transaction signatures are transmitted via NFC.
- Supports multisig co-signing, Lightning Network channel operations, message signing, and PSBTs via HWI for advanced Bitcoin use cases.
- Priced at just $19.99 (regularly $39.99), making it one of the most affordable hardware wallets for Bitcoin self-custody.
- Setup combines user-provided chain code entropy with the card's internal random entropy, preventing Coinkite or any third party from knowing the private key.
- Credit-card form factor (85.6 × 53.98 × 1 mm, 5 g) slips into a regular wallet and enables tap-to-sign via NFC on compatible phones.
Cons
- Bitcoin-only — does not support other cryptocurrencies or tokens.
- No display screen means users must sign transactions blindly, unable to verify transaction details directly on the device itself.
- Backup uses an encrypted XPRV file plus a 16-byte decryption key printed on the card rather than a standard BIP-39 seed phrase, making recovery less intuitive.
- Must be stored in the included RF-blocking sleeve when not in use to prevent unauthorized NFC reading; a lost sleeve must be replaced separately.
- Cannot store arbitrary data or files on the card — only the Bitcoin private key and chain code are held on the device.
- Requires a compatible wallet app (Nunchuk, Sparrow, Bitcoin Keeper, or Cove) to function — cannot be used as a standalone wallet.