Senior Software Engineer, Bitcoin Wallet (Bitkey)

Block is one company built from many blocks, all united by the same purpose of economic empowerment. The blocks that form our foundational teams - People, Finance, Counsel, Hardware, Information Security, Platform Infrastructure Engineering, and more - provide support and guidance at the corporate level. They work across business groups and around the globe, spanning time zones and disciplines to develop inclusive People policies, forecast finances, give legal counsel, safeguard systems, nurture new initiatives, and more. Every challenge creates possibilities, and we need different perspectives to see them all. Bring yours to Block.
The Role
Bitkey is Block's Bitcoin self-custody wallet, built to make it safe and easy for people everywhere to hold their own Bitcoin. Our team is building a product that delivers best-in-class security and usability to a market where people have historically had to sacrifice one for the other. We're finding ways to break those tradeoffs, bridging cryptography with simple, everyday experiences. It's a hard problem - and if that motivates you, you'll be in good company at Bitkey.
We're looking for a Senior Software Engineer who is passionate about Bitcoin and wants to shape the future of self-custody. This role will play a key part in creative innovations in the self custody space while building out platform libraries and services that power Bitkey. You'll help build the secure foundations that our mobile clients and customer experiences rely on.
Candidates may come from backend, platform, or even mobile backgrounds, but success in this role requires deep experience with Bitcoin protocols applied in production and strong engineering fundamentals.
You'll join a mission-driven team that values curiosity, creativity, and collaboration. You'll help us solve real customer problems: protecting funds, enabling recovery, balancing usability with security. You'll also explore innovative unlocks using Bitcoin's building blocks to open up new customer capabilities, recovery paradigms, and security techniques.
You Will

• Design, build, and maintain secure backend services and libraries that enable safe and usable Bitcoin self-custody.
• Create platform primitives and APIs that mobile apps and external clients can rely on.
• Work across boundaries - from cryptographic protocols, to custody flows, to integration with mobile experiences, with a bias toward pragmatic problem-solving.
• Collaborate closely with product managers, designers, and other engineers to deliver solutions that balance usability, availability, and security.
• Take end-to-end ownership of projects, from ideation through execution.

You Have

• A deep interest in Bitcoin and conviction about the importance of self-custody.
• Proven experience shipping production Bitcoin software, or deep protocol expertise with a desire to build for customers, whether from a backend, custody, or mobile background.
• Baseline understanding of secure key management and recovery problems.
• Strong engineering fundamentals and comfort moving across stacks and languages (we use Rust and Kotlin, and can help you learn them if they're new to you).
• A track record of collaborating in cross-functional teams and contributing beyond just code.
• Curiosity, creativity, and a drive to innovate in service of real customer needs.

Nice to Have

• Familiarity with applied cryptographic techniques in Bitcoin custody.
• Experience building SDKs, APIs, or libraries consumed by mobile apps.
• Contributions to open-source Bitcoin projects.
• Experience with security-sensitive or correctness-critical systems

We're working to build a more inclusive economy where our customers have equal access to opportunity, and we strive to live by these same values in building our workplace. Block is an equal opportunity employer evaluating all employees and job applicants without regard to identity or any legally protected class. We will consider qualified applicants with arrest or conviction records for employment in accordance with state and local laws and "fair chance" ordinances. We believe in being fair, and are committed to an inclusive interview experience, including providing reasonable accommodations to disabled applicants throughout the recruitment process. We encourage applicants to share any needed accommodations with their recruiter, who will treat these requests as confidentially as possible. Want to learn more about what we're doing to build a workplace that is fair and square? Check out our I+D page .
While there is no specific deadline to apply for this role, U.S. roles are typically open for an average of 55 days before being filled by a successful candidate. Please refer to the date listed at the top of this job page for when this role was first posted.
Block takes a market-based approach to pay, and pay may vary depending on your location. U.S. locations are categorized into one of four zones based on a cost of labor index for that geographic area. The successful candidate's starting pay will be determined based on job-related skills, experience, qualifications, work location, and market conditions. These ranges may be modified in the future.
To find a location's zone designation, please refer to this resource . If a location of interest is not listed, please speak with a recruiter for additional information.
Zone A:
$217,800 - $326,800 USD
Zone B:
$207,000 - $310,400 USD
Zone C:
$196,100 - $294,100 USD
Zone D:
$185,200 - $277,800 USD
Use of AI in Our Hiring Process
We may use automated AI tools to evaluate job applications for efficiency and consistency. These tools comply with local regulations, including bias audits, and we handle all personal data in accordance with state and local privacy laws.
Contact us at [email protected] with hiring practice or data usage questions.
Every benefit we offer is designed with one goal: empowering you to do the best work of your career while building the life you want. Remote work, medical insurance, flexible time off, retirement savings plans, and modern family planning are just some of our offering. Check out our other benefits at Block.
Block, Inc. (NYSE: XYZ) builds technology to increase access to the global economy. Each of our brands unlocks different aspects of the economy for more people. Square makes commerce and financial services accessible to sellers. Cash App is the easy way to spend, send, and store money. Afterpay is transforming the way customers manage their spending over time. TIDAL is a music platform that empowers artists to thrive as entrepreneurs. Bitkey is a simple self-custody wallet built for bitcoin. Proto is a suite of bitcoin mining products and services. Together, we're helping build a financial system that is open to everyone.