COLDCARD NFC Push TX

Tap any NFC-enabled, internet-connected phone to your COLDCARD to broadcast a signed Bitcoin transaction. No companion app or phone setup required.

What is NFC Push TX?

NFC Push TX opens a broadcast page in the phone's standard web browser. Once enabled on your COLDCARD, sign a transaction and tap any NFC-enabled, internet-connected phone to the device. Nothing needs to be installed or configured on the phone.

How It Works

Sign Transaction: Sign your PSBT on the COLDCARD as usual
Tap: Tap any NFC-enabled phone with Internet access to the COLDCARD
Broadcast: The phone's browser opens and sends the transaction to the Bitcoin network

Key Benefits

No Companion App: Works in the phone's standard web browser
No Phone Setup: No pairing, account, or prior configuration required
Air Gap Maintained: No direct internet connection required on COLDCARD
Multiple Providers: Choose from various service providers or host your own
Privacy Options: Use public services or your own backend for maximum privacy

Supported Devices

This feature is available on COLDCARD Q, Mk5, and Mk4 devices. Enable it and choose a service provider under Settings > NFC Push TX. No phone-side setup is needed.

Privacy Note

For maximum privacy, consider hosting your own Push TX backend. While public services like mempool.space and coldcard.com are trustworthy, using your own service ensures your transaction data stays private.

Try It Now

Test the NFC Push TX functionality with your COLDCARD device.

Go to Push TX

Learn More

For detailed setup instructions and advanced usage, visit our comprehensive documentation.

View Documentation