Casa Blog - Bitcoin Security Made Easy

Casa’s mission has always been to use private keys to enable individuals around the world to achieve personal sovereignty. Private keys unlock freedom — they give an individual the same power, authority, and control over a piece of data as the most powerful government in the world. It’s digital freedom in your pocket, and Casa is making that freedom simple and safe for everyone.

Today I’m excited to announce a new phase in Casa’s journey to bring that empowerment to the world. We’ve raised a $21 million Series A funding round, and we are announcing our newest product: the Casa API.

By integrating the Casa API, developers and companies can connect user wallets for secure visibility and easy bitcoin deposits while keeping private keys fully protected.

Casa API: Enabling builders to easily integrate the benefits of self-custody

As our industry grows, we’re seeing more companies from the “traditional” software and finance world want to integrate bitcoin and its capabilities. They don’t typically have the knowledge in-house to build major pieces of the bitcoin stack, like secure custody, from the ground up. So, they look for a way to integrate a custody offering from another company, and what do they find?

Every single solution is custodial. The ability to integrate a highly secure self-custody solution via an API does not exist.

We saw this problem and realized that the current custodial-focused ecosystem does a disservice to consumers. In a world where Coinbase alone holds more than 10% of all bitcoin in existence, it's more important than ever for people to have the choice to be their own bank. After all, the first sentence of the bitcoin whitepaper is about using money without going through a financial institution.

“A purely peer-to-peer version of electronic cash would allow online payments to be sent directly from one party to another without going through a financial institution.” - Satoshi Nakamoto

The Casa API fixes this. Now, a thriving ecosystem will be built around self-custody, enhancing consumers' ability to use their private keys as freedom technology. Companies and developers who want to give their customers the benefits of bitcoin self-custody don’t have to build a fully secure wallet stack on their own. Instead, they can lean on Casa’s years of experience and security expertise to give their customers what they need.

We’re starting with two simple features for our API: View Balance and Deposit to Casa. View Balance allows you to view the balance in your Casa wallet from another app once you connect your wallet. Deposit to Casa allows you to click one button to send bitcoin to your Casa wallet, with no need to copy/paste an address and quadruple-check it before anxiously hitting Send.

Casa API will launch this summer in a closed beta with a few special launch partners that showcase many different uses of the API.

Why use an API instead of a xpub?

If you’ve ever shared your public keys or xpub with an app, you might be wondering why an API is necessary. Why would you want to give this type of access to your Casa account?

Setting aside the consideration that not all companies want to build in the functionality of utilizing xpubs, there are some benefits to connecting your Casa account instead of providing an xpub:

  • Privacy: When you provide an xpub to a product for viewing your balance or sweeping funds, that product now has full access to find any on-chain transaction by any of your wallet addresses, forever. Using the Casa API, you can provide a single address at a time for auto-sending funds, and you can revoke access for viewing at any time. The Casa API gives you more control over who views your funds and when.
  • Flexibility: For multisig users, it’s not possible to provide a single xpub and let it sync your balance in another product. Since you have multiple keys protecting your bitcoin, you have multiple xpubs. The product would need to build out bitcoin scripting capabilities to combine those xpubs into viewing a multisig script, which to date nobody has done (because it’s complicated!). This allows you to build products that leverage Casa’s multisig expertise without requiring you to keep your funds in a single-signature wallet or on an exchange to make them viewable.

We’re excited to help build amazing products using the Casa API, and we can’t wait to enable new ways for companies to give their users the benefits of self-custody.

If you’re interested in participating in the Casa API closed beta, please fill out this form.

Series A fundraise: Fueling our next phase of growth

Last December, we closed a $21 million (because of course, it was going to be 21 million) Series A raise. The round was led by Acrew Capital, with participation from Positive Sum, Avon Ventures, Tioga Capital, Stillmark, Castle Island Ventures, Lerer Hippeau, Naval Ravikant, Scott Belsky, Todd McKinnon and Freddy Kerrest of Okta, and others.

We have an incredibly strong bench of investors supporting Casa as we take our next steps toward accomplishing our mission of bringing private keys to the world.

Startup culture often views a successful fundraise as the end of the line — mission accomplished. This couldn’t be farther from the truth, and at Casa, we view it as the beginning of a new chapter as we build the future we want to live in.

The next few years will be the biggest and most exciting yet for Casa. We can’t wait to share everything else we have in the works.

Want to help empower the world with private keys?

If you want to join us in our mission, check out our jobs page for open roles. If you don’t see a role that fits but feel you have something special to contribute, email us at jobs [at] with your best pitch.