Machine Learning Engineer, Fraud Risk

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 Team
Marketplace under Cash App provides different payment products such as BNPL (Buy Now, Pay Later) or pay monthly to customers. The Fraud Risk team is responsible for building scalable systems that power our modelers and decision scientists to develop & deploy ML-based strategies to battle fraudsters to ensure the health of the business. In addition, we build end-to-end customer experience for risk assessments.
As a member of the team, you will work as a Full Stack Engineer, utilising your AWS and Kubernetes experience to help develop the next generation of automation tools within the risk domain. Your contributions will play a key role in driving initiatives aimed at building scalable and robust solutions. This is an exciting opportunity to make a direct, tangible impact on our product and work on projects that are pivotal to the business's success.
You Will

• Develop highly scalable systems, algorithms, and tools on one platform to support software solutions
• Develop, integrate, and optimize ML and software systems
• Demonstrate rigor in high code quality, good test coverage, and other engineering best practices
• Collaborate with product, analysts, and modelers on planning and implementing frictionless user experiences
• Have autonomy to research and achieve outcomes with support when you need it
• Contribute to the growth of our development capabilities through leading, mentoring, and supporting fellow engineers
• Responsible for designing, building, and owning the services and infrastructure that manage Afterpay's financial risk
• Work where you like, in any AU Cash App office location or remotely in Australia

You Have

• 6+ years of backend software development experience in building and maintaining applications in any mainstream language such as: Java, JavaScript, Python, Kotlin, Ruby, Go, Swift, C++
• Enthusiastic about solving business problems with technology and can take ownership of an end-to-end solution
• Passionate about continuously learning new technologies, frameworks, and services
• Possess an execution mindset and the ability to deliver with cross-functional teams that are globally distributed
• Serious about testing and have experience with automated testing frameworks
• Passion for Cash App's mission of economic empowerment
• Experience of DevOps (AWS / Kubernetes / CICD) experience is a bonus
• Experience of ML model-related experience is a bonus
• Experience with common technologies, for example, Kafka, Redis, Cassandra is a bonus
• A keen interest in advancing Cash App's vision of building for economic empowerment

Tools we use and teach

• Python, Java, Kotlin, Javascript
• Onnx/PyTorch, LightGBM/XGBoost
• Kubernetes, AWS
• Datadog, Buildkite
• Hibernate, MySQL, Cassandra DB, DynamoDB
• HTTP, JSON, gRPC, Protocol Buffers
• Kafka, Temporal, event-driven microservice architecture

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.