Senior Software Engineer - Product Security

  • Full-time

Company Description

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 app, bringing a better way to send, spend, invest, borrow and save to our millions of monthly active users. With a mission to redefine the world's relationship with money by making it more relatable, instantly available and universally accessible, at Cash App you'll have the opportunity to make a real-world impact with your career.

Today, Cash App has thousands of employees around the world with a culture geared toward creativity, collaboration and impact. We’ve been a distributed team since day one, and continue to value working across time zones and continents both remotely and in our Cash App offices.

Our offices are great, but many of our roles can be done remotely from the countries where Block operates. We tailor our experience to champion our employees’ creativity and productivity wherever they are. 

Check out our locations, benefits and more at

Job Description

At Cash, security is everyone’s responsibility, especially among engineering disciplines. The product security engineering team focuses on empowering its partners to incorporate security directly into their SDLC with confidence. 

The team is a hands-on, engineering-driven security team, which aligns security engineers toward product teams, across the entire Cash App organization. As a security team, we collaborate on building and sharing security infrastructure, design patterns, and guidelines. We accomplish this by treating security engineering as a discipline, offering our expertise to technical and non-technical stakeholders. We secondarily abstract bespoke security solutions into reusable infrastructure, sharing our learnings, best practices and final solutions across the organization. Our mission is to make secure development the easiest and most secure path for all other engineers.

As a Product Security Engineer, you’ll work within the engineering organization to:

  • Co-design, co-build, and co-own the security and privacy mechanisms and features which support the internal engineering teams and customer operations.
  • Design, apply, and develop cryptographic primitives to protect data.
  • Understand how to apply and advise product teams on security requirements to the product’s implementation and how specific regulatory data privacy considerations may be relevant.
  • Drive the direction of the organization by productizing common security patterns and working toward our security roadmap
  • Help the engineers around you level-up on their own security reasoning and knowledge.


You have:

  • A strong motivation to contribute to a meaningful product that will fundamentally change the way people interact with financial institutions
  • You enjoy solving problems at scale, through hands-on programming and documentation
  • Strong desire to perform and grow as a security engineer and educate other engineers
  • Demonstrated technical initiative and leadership
  • Enthusiastic about distributed workforces and effective at working asynchronously
  • An interest in working on a product that impacts people/businesses directly
  • You have an aptitude for security and strong software engineering fundamentals

Tools we use and teach:

  • AWS KMS and Google’s Tink Cryptographic APIs
  • Java 11 including JUnit, Hibernate, and Guice
  • Kotlin
  • HTTP, JSON, gRPC, and Protocol Buffers
  • MySQL, DynamoDB
  • Operating microservices, Kubernetes, Terraform

Additional Information

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 a proud equal opportunity employer. We work hard to evaluate all employees and job applicants consistently, without regard to race, color, religion, gender, national origin, age, disability, veteran status, pregnancy, gender expression or identity, sexual orientation, citizenship, or any other legally protected class. 

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

Additionally, we consider qualified applicants with criminal histories for employment on our team, assessing candidates in a manner consistent with the requirements of the San Francisco Fair Chance Ordinance.

Block, Inc. (NYSE: SQ) is a global technology company with a focus on financial services. Made up of Square, Cash App, Spiral, TIDAL, and TBD, we build tools to help more people access the economy. Square helps sellers run and grow their businesses with its integrated ecosystem of commerce solutions, business software, and banking services. With Cash App, anyone can easily send, spend, or invest their money in stocks or Bitcoin. Spiral (formerly Square Crypto) builds and funds free, open-source Bitcoin projects. Artists use TIDAL to help them succeed as entrepreneurs and connect more deeply with fans. TBD is building an open developer platform to make it easier to access Bitcoin and other blockchain technologies without having to go through an institution.

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