Staff Software Engineer in Belfast

Apex Fintech Solutions (AFS) powers innovation and the future of digital wealth management by processing millions of transactions daily, to simplify, automate, and facilitate access to financial markets for all. Our robust suite of fintech solutions enables us to support clients such as Stash, Betterment, SoFi, and Webull, and more than 20 million of our clients' customers. Collectively, AFS creates an environment in which companies with the biggest ideas in fintech are empowered to change the world. As a global organization, we have offices in Austin, Dallas, Chicago, New York, Portland, Belfast, and Manila. If you are seeking a fast-paced and entrepreneurial environment where you'll have the opportunity to make an immediate impact, and you have the guts to change everything, this is the place for you.

ABOUT THIS ROLE

We’re seeking an innovative, passionate, and forward-thinking individual to join us as a Staff Software Engineer. This is an opportunity to join a fast-paced team with the urgency of a startup and the expertise of an established organisation. Due to the space we innovate in, your products will process billions of transactions per day in real-time and power both startup and established industry participants. As a Staff Platform Engineer in this multi-disciplinary team, you will play an integral role in designing, implementing, and optimizing our Billing services, tooling, and infrastructure to ensure robust, scalable and accurate billing to our clients.

Duties/Responsibilities

• Design and evolve microservices architecture for the billing platform, ensuring scalability, reliability, and maintainability across the distributed system.
• Lead technical decision-making for complex billing workflows involving rate configurations, charge calculations, settlement generation, and end-customer processing, balancing business requirements with system performance and cost constraints.
• Drive performance optimization of data-intensive operations leveraging BigQuery, PostgreSQL, and caching strategies to handle high-volume financial calculations and reporting at scale.
• Mentor and guide engineers across multiple teams, establishing best practices for Java development, Bazel build configurations, database migrations with Flyway, and event-driven architectures.
• Own system reliability and operational excellence, implementing comprehensive monitoring with Datadog, designing robust error handling and validation, and ensuring SLOs are met for critical financial processes.
• Collaborate cross-functionally with product, finance, and compliance teams to translate business requirements into technical solutions, managing integrations with external financial systems and internal platform services.
• Establish and maintain technical standards for the billing domain, including testing strategies, API design with gRPC and Protobuf, database schema evolution, and deployment practices across multiple environments.

Education and/or Experience

• Bachelor's degree in Computer Science, Engineering, or related field (or equivalent work experience) required; advanced degree preferred.
• 8+ years of experience in software development with a deep knowledge in one or more programming languages, including Java, Python.
• Experience with automated testing frameworks and methodologies for backend services.
• Experience contributing to topics and participating in technical direction and implementation strategy for projects.
• Experience with CI/CD (Continuous Integration/Continuous Deployment) pipelines and tools, automating build, test, and deployment processes.
• Experience with cloud platforms (e.g., AWS, Azure, GCP).
• Experience with SQL including the ability to write complex queries and optimise database performance, e.g. Postgres, MS SQL Server.
• Experience in financial services a plus.

Required Skills/Abilities

• Expertise with containerization (Docker), orchestration (Kubernetes), cloud platforms (GCP, AWS), and infrastructure automation (Terraform, Ansible).
• Expertise in software release tooling, GitOps, and CI/CD practices.
• Excellent communication skills and the ability to collaborate effectively with cross-functional teams.
• Knowledge of API management methodologies, security practices, and traffic management strategies.

This job operates in a hybrid office environment 2 days per week.