Senior Software Engineer, Libraries and Frameworks

  • San Francisco, CA
  • Full-time

Company Description

We believe the economy is better when everyone has access. When everyone has room to grow. No one should be left out because the cost is too great or the technology too complex. We started with a little white credit card reader but haven’t stopped there. We’re empowering the independent electrician to send invoices, setting up the favorite food truck with a delivery option, helping the ice cream shop pay its employees, and giving the burgeoning coffee chain capital for a second, third, and fourth location. We’re here to help sellers of all sizes start, run, and grow their business—and helping them grow their business is good business for everyone.

Job Description

Libraries and Frameworks is an internal product team that ships multiple platforms upon which product teams build server-side products on. This team supports 3 different programming languages - Java, Go and Ruby - and provides a best-of-breed set of tools, libraries and frameworks for each, typically leveraging open source components and industry standards as much as possible.

We’re seeking a senior engineer who has experience delivering frameworks. Open source experience is a strong plus, particularly with strong participation in one or more of the Java, Go or Ruby communities. You should be passionate about clean library API design, have empathy for engineers who use your libraries and frameworks, and care about improving engineer velocity.


You have:

  • Proficiency in either of Java, Go or Ruby

  • The ability to troubleshoot functional and performance issues in language runtimes and third-party libraries

  • Maintained and shipped libraries

  • A proven track record in rolling out changes to a large number of engineers who use your libraries in a safe yet expedient manner

  • A passion for library API design

  • 5+ years professional experience

Languages and technologies we use:

  • Java, Go, Ruby

  • Hibernate, Jetty, gRPC, JOOQ, Envoy, Rails

Additional Information

At Square, our purpose is to empower – within and outside of our walls. In order to build the best tools for the businesses and customers we support all over the world, we have to start at home with a workforce as diverse and empowered as our sellers. To this end, we take great care to evaluate all employees and job applicants equally, based on merit, competence, and qualifications. We do not discriminate on the basis of race, religion, color, national origin, gender, sexual orientation, age, marital status, veteran status, disability status, or any other characteristic protected by law. We encourage candidates from all backgrounds to apply and always consider qualified applicants with arrest and conviction records, in accordance with the San Francisco Fair Chance Ordinance. Applicants in need of special assistance or accommodation during the interview process or in accessing our website may contact us by sending an email to assistance(at) We will treat your request as confidentially as possible. In your email, please include your name and preferred method of contact, and we will respond as soon as possible.