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.

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. 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.

• 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.

• 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.

• 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.

We offer a robust package of employee perks and benefits, including a market-leading salary with an annual bonus, 28 days of annual leave plus 10 Northern Ireland national holidays, a training and development budget, and a pension matched up to 7%. Our benefits also cover private health insurance for medical, dental, and optical care, and life insurance. We emphasize work-life balance with flexible working hours, parental leave, a modern city center office, and a hybrid work schedule that allows for greater flexibility by partially working from home. Additional perks include monthly catered lunches, unlimited drinks and snacks, hackathon events, poker tournaments, and a charitable matching gift program.

Apex Fintech Solutions is an equal opportunity employer that does not discriminate on the basis of race, color, religion, sex (including pregnancy, sexual orientation, and gender identity), national origin, age, disability, veteran status, marital status, or any other protected characteristic. Our hiring practices ensure that all qualified applicants receive fair consideration without regard to these characteristics.

Apex Fintech Solutions is committed to creating an inclusive and accessible workplace for all candidates, including those with disabilities. We are dedicated to ensuring equal employment opportunities and providing reasonable accommodations to qualified individuals with disabilities.