People Matter

Senior Software Engineer, Fraud Risk



Software Engineering, Accounting & Finance
Galway, Ireland
Posted on Sunday, June 30, 2024

Company Description

Since we opened our doors in 2009, the world of commerce has evolved immensely, and so has Square. After enabling anyone to take payments and never miss a sale, we saw sellers stymied by disparate, outmoded products and tools that wouldn’t work together.

So we expanded into software and started building integrated, omnichannel solutions – to help sellers sell online, manage inventory, offer buy now, pay later functionality through Afterpay, book appointments, engage loyal buyers, and hire and pay staff. Across it all, we’ve embedded financial services tools at the point of sale, so merchants can access a business loan and manage their cash flow in one place. Afterpay furthers our goal to provide omnichannel tools that unlock meaningful value and growth, enabling sellers to capture the next generation shopper, increase order sizes, and compete at a larger scale.

Today, we are a partner to sellers of all sizes – large, enterprise-scale businesses with complex operations, sellers just starting, as well as merchants who began selling with Square and have grown larger over time. As our sellers grow, so do our solutions. There is a massive opportunity in front of us. We’re building a significant, meaningful, and lasting business, and we are helping sellers worldwide do the same.

Job Description

Risk Engineering works to protect Square and our customers $25B+ in payments from fraud and payment disputes. We build systems to detect and respond to potential fraud threats, provide outstanding tools to agents for investigating fraud events, and give our customers seamless web and mobile experiences to manage and fight payment disputes. Our mission is to protect Square, protect our customers, and make a complicated and sometimes painful process understandable to all.

Fraud Risk is looking for a Senior Software Engineer to help us build solutions that further these goals. You will collaborate with teams across the company on new product and market launches to fight fraud and make realtime data available for scalable ML-based fraud decisioning. Help us solve these challenging problems with data science, machine learning, and efficient tooling!

You will:

  • Work with teams and roles across Square to develop new solutions and improve existing processes addressing fraud

  • Develop essential tooling to act quickly on potential fraud

  • Design fault-tolerant systems so the team can be brave, move fast, and break things, without ever showing a negative impact to customers

  • Advocate and model engineering best practices

  • Mentor other engineers


You have:

  • 5+ years of software engineering experience

  • Interest in working full-stack across multiple technical domains, including backend microservices and internal tooling

  • Experience building products end to end - technical design, implementation, testing, launch, and maintenance

  • Metrics-oriented mindset: you want your work to be measurable and impactful

  • Comfortable working with a globally distributed team of data scientists, engineers, and risk experts

Technologies we use and teach:

  • Java, Guice, Google Cloud Platform, Amazon Web Services

  • Go, Ruby on Rails, Ember, React, GraphQL

  • Protocol Buffers

  • MySQL, Hibernate, jOOQ

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, based solely on the core competencies required of the role at hand, and without regard to any 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.


We want you to be well and thrive. Our global benefits package includes:

  • Healthcare coverage
  • Retirement Plans
  • Employee Stock Purchase Program
  • Wellness perks
  • Paid parental leave
  • Paid time off
  • Learning and Development resources

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.