Coinkite Tapsigner

Overview

The Coinkite Tapsigner is a Bitcoin signing key sealed inside a standard bank-card form factor. There's no screen, no battery, and no buttons — you tap it to an NFC-capable phone, and a compatible app uses the card's secure element to sign. It slips into a wallet alongside your other cards and is priced very low, making it one of the most affordable and portable ways to hold a hardware-backed Bitcoin key. It's built by Coinkite, the same trusted maker behind the Coldcard.

The Tapsigner's private key is generated inside the secure element and never leaves it; the card signs transactions on-tap. It's designed to work as a companion or backup key rather than a full standalone wallet — it shines as one signer in a multisig setup, or as a convenient pocketable key you pair with a mobile app. Because it's a sealed card, it's discreet and durable.

The honest trade-offs mirror other screenless card wallets: with no display of its own, you verify transaction details on your phone, so you're trusting the phone's screen and the app more than a device that shows the destination itself. Its firmware is only partially open-source. And its card format means it's dependent on NFC-capable phones and compatible apps. For someone who wants a cheap, pocketable NFC signing key — especially as part of a multisig or as a companion to a Coldcard — the Tapsigner is a clever, well-made device; for a primary standalone wallet, a device with its own screen is safer.