Freelance Algorithmic Trading Software Developer Jobs in St Louis, MO

We invite you to join Mastercard’s global credit card authorization program, where you’ll help facilitate billions of transactions among issuers, acquirers, and service providers worldwide. As a Software Engineering Manager, you will lead a cross‑functional team and shape the strategic direction of critical payment systems. You will drive engineering excellence across software design, development, testing, security, performance, operability, and delivery, ensuring solutions are scalable, resilient, and aligned with Mastercard’s enterprise objectives.

• Team Leadership & Development: Serve as a servant leader for a cross‑functional engineering team, including Software Engineers, Technical Program Managers, and Product Manager‑Technical roles. Recruit, develop, and retain top engineering talent. Coach and mentor engineers, conduct performance reviews, and plan career development.
• Engineering Strategy & Enterprise Leadership: Partner with product, architecture, and business stakeholders to define technical strategies that support team objectives and broader enterprise priorities. Translate business needs into actionable engineering roadmaps. Promote cross‑team collaboration, platform reuse, and shared engineering practices.
• Software Architecture & Design: Collaborate with architects and senior engineers to design scalable, secure, maintainable, and highly available systems. Review and approve software designs and architectural decisions in line with enterprise standards. Guide teams in modern architecture patterns, API‑first design, and event‑driven architectures.
• Software Development & Engineering Excellence: Remain technically engaged and guide best practices across the SDLC. Promote clean code, reusable components, and engineering craftsmanship. Review designs, code, and implementations with an emphasis on quality, security, resiliency, and performance. Guide engineers in applying effective data structures, algorithms, and performance‑aware design techniques.
• Testing & Quality Engineering: Establish and promote unit, functional, integration, and automated testing practices. Ensure appropriate test coverage and integration into CI/CD pipelines. Drive quality engineering practices that improve reliability and reduce defects.
• Performance Engineering: Drive performance testing, benchmarking, scalability analysis, and system tuning. Optimize applications for high‑volume, low‑latency transaction processing. Partner with engineers to eliminate bottlenecks through effective design and algorithm selection.
• Secure Software Engineering: Enforce secure coding standards and security best practices. Promote threat modeling, secure architecture reviews, and vulnerability management. Ensure applications meet Mastercard security requirements and industry standards.
• Operability & Reliability Engineering: Own operational health, observability, monitoring, logging, alerting, and supportability. Drive practices that improve reliability, availability, and maintainability. Support Site Reliability Engineering and DevOps initiatives.
• Troubleshooting & Incident Management: Lead teams in diagnosing and resolving complex production issues. Facilitate root cause analysis and implement corrective actions. Provide leadership during production incidents to restore service swiftly and minimize impact.
• Delivery & Execution: Drive execution of strategic initiatives while balancing business priorities, technical debt, and team capacity. Own delivery of health, risk management, and stakeholder communication. Make rapid decisions in fast‑paced environments and communicate updates to senior management.

• Proven experience leading high‑performing software engineering teams.
• Hands‑on experience with Java, C/C++, or similar object‑oriented languages.
• Design experience for scalable, secure, highly available, and resilient distributed systems.
• Experience building and operating high‑volume, low‑latency transaction processing platforms.
• Strong understanding of software architecture, API design, microservices, and event‑driven systems.
• Strong knowledge of testing practices, including unit, functional, integration, and automated testing frameworks.
• Experience with performance engineering, capacity planning, system optimization, and scalability testing.
• Deep knowledge of secure coding practices, application security principles, and secure SDLC methodologies.
• Strong grasp of observability, monitoring, operational readiness, and reliability engineering practices.
• Demonstrated ability to apply computer science fundamentals—data structures, algorithms, and performance optimization techniques.
• Experience conducting code reviews and establishing engineering quality standards.
• Strong analytical, problem‑solving, troubleshooting, and decision‑making skills.
• Ability to develop and communicate technical vision and engineering strategy.
• Enterprise mindset focused on business outcomes and cross‑functional collaboration.
• Proven ability to drive organizational change, technology adoption, and continuous improvement initiatives.
• Strong communication and stakeholder management skills at all organizational levels.
• Capability to inspire teams, navigate ambiguity, and consistently deliver results in a complex environment.

Mastercard is a merit‑based, inclusive, equal opportunity employer that considers applicants without regard to gender, gender identity, sexual orientation, race, ethnicity, disability, veteran status, or any other characteristic protected by law. We hire the most qualified candidate for the role. In the US or Canada, if you require accommodations or assistance to complete the online application process or during the recruitment process, please contact reasonable_accommodation@mastercard.com and identify the type of accommodation or assistance you are requesting. Do not include any medical or health information in this email.

• Abide by Mastercard’s security policies and practices.
• Ensure the confidentiality and integrity of the information being accessed.
• Report any suspected information security violation or breach.
• Complete all periodic mandatory security trainings in accordance with Mastercard’s guidelines.

O’Fallon, Missouri: $140,000 - $231,000 USD