Depiction of a Coldcard hardware wallet

New Coldcard Hardware Wallet Integration

With Pocket we offer you the easiest way to buy your bitcoin directly into your own wallet. Our various wallet integrations help you connect your wallet to Pocket in just a few clicks. Today we are happy to announce another integration for the Coldcard hardware wallet.

New Coldcard integration

Starting today, it's easier than ever to use your Coldcard hardware wallet securely with Pocket. With the new Coldcard integration, you can access your Bitcoin address entirely from your Coldcard's SD card without ever having to connect your Coldcard to your computer. The ability to use your wallet without a physical connection is also known as "air-gapped".

Simply select the Coldcard in the Pocket setup process and confirm that you will perform the process via SD card.

Screenshot of the wallet selection on the Pocket website
The new Coldcard integration in Bitcoin wallet overview

You will next be given the option to select your Bitcoin address. Instead of your Bitcoin address itself, you specify the derivation path of it. Based on this path your Coldcard will derive the correct Bitcoin address by itself. The default derivation path points to your first address of your first account (84'/0'/0'/0/0).

Screenshot of the Coldcard derivation path selection on the Pocket website
Enter the derivation path of your Bitcoin address

Then download the coldcard.txt file and save it to your Coldcard SD card. Afterwards you can select the saved file via Advanced/Tools -> File Management -> Sign Text File and sign it.

Screenshots of the Coldcard menu up to the signature menu
Coldcard menu navigation to the signature function

Take your SD card out of your Coldcard and connect it to your computer again. Now you will find the signed file coldcard-signed.txt on the card, which you can upload to Pocket.

Screenshots of the content of the Coldcard SD-card
The signed file `coldcard-signed.txt` on the Coldcard SD card

With your Bitcoin address and the signature in coldcard-signed.txt, Pocket can now make withdrawals directly into your Coldcard wallet. Now confirm the Bitcoin address and complete your order to receive your bitcoin purchase payment details.

Screenshot of a successfully shared Bitcoin address on the Pocket website
Your successfully shared Bitcoin address

How do I share multiple Bitcoin addresses? (XPub)

Pocket is especially popular for recurring bitcoin purchases. Once you set up Pocket, you can reuse your payment details at will to receive bitcoin into your wallet again.

To avoid having to pay out your bitcoin to the same Bitcoin address every time, we recommend that you share multiple Bitcoin addresses with Pocket using your extended public key (xpub).

To do this, click on the option to share your entire wallet with Pocket.

Screenshot of the option to share an entire wallet on the Pocket website
The option to share your entire wallet with Pocket

To retrieve your xpub, you can export your wallet on your Coldcard via Advanced/Tools -> File Management -> Export Wallet.

Screenshots of the Coldcard menu to export your wallet
Coldcard menu navigation to the wallet export function

When exporting your wallet, select the Generic JSON option and next specify the same account number you used in your derivation path. Make sure that you create a separate account for Pocket. We recommend that you use the account number 1 here.

Coldcard menu screenshots to export a specific wallet account
Coldcard menu navigation to JSON export of a specific wallet account

Once you have exported your xpub to the coldcard-export.json file, you can now copy the xpub from it to the Pocket website.

Congratulations, with every bitcoin purchase your bitcoin will now automatically end up on an unused Bitcoin address of your Coldcard wallet.

Screenshot of your successfully shared Bitcoin wallet on the Pocket website
Your successfully shared Bitcoin wallet addresses

Try it now

We hope you like this new feature and make use of it. Let us know if you have any open questions about the setup. There are many more interesting things to learn about the Coldcard and the xpub, which we will cover in a separate article soon.

Until then, happy stacking! 🎁


Congratulations! 🥳

Your bank payment arrived and was successfully exchanged into bitcoin.

Your bitcoin are soon on the way to your Bitcoin wallet.

Bitcoin purchase

Bank payment:EUR 100.00

Purchased:BTC 0.00435850

Exchange rate:EUR 22,599.90 / BTC