Senior Staff Software Engineer, Financial Platform (Transaction Health)

It all started with an idea at Block in 2013. Initially built to take the pain out of peer-to-peer payments, Cash App has gone from a simple product with a single purpose to a dynamic ecosystem, developing unique financial products, including Afterpay/Clearpay, to provide a better way to send, spend, invest, borrow and save to our 50+ million monthly active customers. We want to redefine the world's relationship with money to make it more relatable, instantly available, and universally accessible.

Today, Cash App has thousands of employees working globally across office and remote locations, with a culture geared toward innovation, collaboration and impact. We've been a distributed team since day one, and many of our roles can be done remotely from the countries where Cash App operates. No matter the location, we tailor our experience to ensure our employees are creative, productive, and happy.

The Role

Cash App's Transaction Health team is responsible for ensuring the reliability, scalability, and correctness of our card transaction processing platform. We power 1 billion+ card transactions and securely move billions in Gross Payment Volume (GPV) annually across Cash App and Square in the US and Canada. Our work is mission-critical, directly impacting millions of customers by ensuring every transaction is processed seamlessly, correctly, and at scale.

As a Senior Staff Software Engineer, you will be a technical leader driving architectural decisions, improving system resilience, and enabling new financial products. You will work across teams, solving some of the hardest engineering challenges in fintech while shaping the future of our platform.

Our team is distributed across Australia and the US, and we embrace a highly collaborative and inclusive culture, ensuring seamless teamwork across time zones.

You Will

• Lead and influence key architectural decisions to ensure our platform remains scalable, reliable, and secure.
• Solve complex technical challenges related to high-throughput, low-latency transaction processing.
• Drive and influence cross-org efforts, collaborating with engineering teams, product teams, and financial partners to build and scale new financial products.
• Own and deliver critical projects, ensuring successful execution through the entire software development lifecycle.
• Improve operational excellence, establishing best practices for reliability, observability, and performance at scale.
• Mentor and uplevel engineers, helping to grow technical expertise within the team.

You Have

• 12+ years of experience designing and delivering highly scalable, high-volume distributed systems.
• Proven leadership in driving large, cross-functional projects, influencing both technical and product strategy.
• Expertise in architecting and scaling financial infrastructure, ideally in payments, banking, or fintech.
• Deep technical knowledge of backend engineering, distributed systems, and financial transaction processing.
• Strong problem-solving skills with the ability to diagnose complex systems with many moving parts.
• Excellent communication and collaboration skills, capable of working across teams and influencing key stakeholders in a distributed team environment.

Technologies We Use and Teach

• Languages: Java, Kotlin, Go
• Infrastructure: Kubernetes, AWS
• Data & Messaging: Kafka, DynamoDB, MySQL
• Frameworks: Hibernate, Guice, GRPC, JUnit

If you're passionate about scaling financial infrastructure, improving transaction reliability, and solving complex engineering challenges at a high-impact fintech company, we'd love to hear from you!

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.