Senior Software Engineer (Trade Execution)

About the role

Apex Fintech Solutions (Apex) powers innovation and the future of digital wealth management by building tech-forward solutions that help simplify, automate, and facilitate access to financial markets for all. Our robust suite of fintech software enables us to support clients such as Stash, Betterment, SoFi, Webull, and eToro, amongst many others; collectively, Apex powers access to the stock market for over 22+ million end customers. At Apex, we are changing how the securities industry operates by reinventing the status quo, which was manual, slow, and accessible only by the ultra-wealthy. We're digitizing and democratizing systems so that everyone has an opportunity to invest. When you're at Apex, you drive this change. You're part of a global team with a clear vision: to be the trusted technology that powers the digital economy. Our offices in Austin, Dallas, Chicago, New York, Portland, Belfast, and Manila are home to over 1,000 employees. Together, we're shaping the future of financial innovation. Embrace change. Solve big. Win together. And be G.R.E.A.T. - grit, results, empathy, accountability, and teamwork - with Apex. We're proud to be recognized for the innovative work we do, the purpose-driven nature of our work, and the collaborative culture we've created. Here are just a few of the many awards we've recently received: Best Places to Work 2026, 2025, 2024, 2023 - Presented by BuiltIn WealthTech of the Year 2025 - Presented by US FinTech Awards The World's Top 250 Fintech Companies 2024 - Presented by CNBC ABOUT THIS ROLE Apex Fintech Solutions is looking for an experienced Senior Software Engineer with a strong focus on backend systems to join our Trade Execution team. While prior experience with C++ or C# is not mandatory, candidates must demonstrate a willingness to learn and work with these languages in the near term. This role is critical in designing, building, and maintaining scalable backend systems that power our multi-asset trading platform that US markets. This position is ideal for engineers passionate about backend development, tackling complex problems, and building systems that scale efficiently. Duties/Responsibilities Design, develop, test, deploy, maintain, peer-review, and continuously tune high-performance, high-throughput software. Collaborate with other members of the team to share, learn, develop, and deliver designs and coding standards to meet the growing needs of the platform Build resilient, self-scaling, self-healing services that deliver the highest level of reliability. Support the production systems that you design. This includes building, deploying (CI/CD), and monitoring (DataDog, Grafana, Prometheus, PagerDuty). Write commercial grade, well-tested code, and maintain high code-quality standards across your team through code reviews and other best practices. Implement instrumentation to maintain observability to proactively visualize opportunities for improvement. Education and/or Experience Bachelor's in Computer Science, Software Engineering, or a related discipline (or equivalent work experience required) 5+ years of professional experience developing backend systems. Strong experience with SQL databases, including query optimization, indexing, schema design, and troubleshooting. Experience and knowledge of Linux, socket programming, concurrency and lock free data structures. Experience integrating and developing APIs for efficient data flows. Experience in execution management. Experience with kernel bypass networking preferred. Experience building microservices or working with distributed systems preferred. Experience building/maintaining backend trading execution systems preferred. Exposure to Agile methodologies or iterative development practices preferred. Required Skills/Abilities Backend development expertise with proficiency in a modern programming language (e.g., C++, C#, Python, Java, Go, etc.). Fundamental understanding of C++ and/or C# concepts, with a commitment to learning and utilizing these languages in the near term. Solid knowledge of system architecture, backend design patterns, and scalable infrastructure. Strong debugging and troubleshooting skills for application and system-level issues. Familiarity with version control systems (Git) and CI/CD pipelines in backend workflows. Exceptional problem-solving and analytical thinking skills. Strong communication and teamwork abilities, with experience collaborating across teams. Proven track record of learning and adapting to new technologies and environments. Work Environment This job operates in a hybrid, office environment 3 days per week. #engineering #mid-senior #full-time #LI-SD1 #APEX Please note this job description is not designed to cover or contain a comprehensive listing of activities, duties, or responsibilities required of the employee for this job. Duties, responsibilities, and activities may change at any time with or without notice. O