Sr. Software Engineer I (Scala)

ninjatrader; United States; On-site; USD 140,000 - 190,000; Full time

Job summary

NinjaTrader in the United States seeks a Sr. Software Engineer to join our Evaluation Services team. You will design, build, and maintain the Scala-based backend systems powering our auto-liquidation engine, risk evaluation, and trading services.

You will own features end-to-end, collaborate with Trading Services, Solutions Engineering, and Product, and mentor junior engineers while delivering production-ready, scalable systems in a fast-paced environment.

Qualifications

• 5+ years of backend software engineering experience in production systems
• Expertise in Scala and functional programming
• Experience with actor-based concurrency (Akka/Pekko)
• Proficient with PostgreSQL and JSONB
• Experience with Kafka or Pub/Sub and event-driven architectures
• Strong debugging and incident response skills

Responsibilities

• Design and implement backend services in Scala for evaluation, risk, and trading service workloads
• Build actor-based systems handling market data, position changes, and events
• Own features end-to-end from spec to production handoff
• Design data models and PostgreSQL schemas, including JSONB
• Diagnose and resolve production incidents and edge cases
• Drive code quality through PR reviews and testing
• Translate business requirements into well-scoped stories
• Contribute to architectural decisions and debt remediation
• Mentor junior team members on Scala and testing
• Develop deep expertise in NinjaTrader's evaluation platform and integrations

Skills

Scala

Backend engineering

Actor-based concurrency (Akka/Pekko)

PostgreSQL

Kafka / Pub/Sub

ScalaTest

Troubleshooting

Data modeling

Tools

Akka/Pekko

PostgreSQL

Kafka

ScalaTest

Job description

JOIN US ON OUR MISSION TO BECOME THE #1 RETAIL TRADING PLATFORM IN THE WORLD

Welcome to the dynamic world of NinjaTrader! As an industry-leading trading platform and futures broker, we're empowering traders to take control of their financial destiny. How do we do it? We provide cutting-edge products and services that enhance the trading journey. Whether a seasoned pro or just starting out, NinjaTrader equips traders with award-winning software and brokerage services to navigate the world's leading financial markets with confidence.

Our growth story is nothing short of exhilarating. Since 2003, NinjaTrader has been dedicated to understanding and supporting traders on their journey toward trading triumph. Through those efforts, our user base has grown to over 2 million users and we have become the number one rated futures brokerage worldwide.

But we're not stopping there. We're constantly evolving, pushing boundaries, and modernizing the futures industry. Our commitment to innovation means users will always have access to dynamic tools, real-time support, and a community of like-minded traders.

So, why work at NinjaTrader? Here, you're not just part of a team; you're part of a movement. We empower employees to reach new heights in their careers by providing a dynamic culture focused on social connection, professional development, and employee recognition initiatives. Sounds too good to be true? Take it from our employees.

Join us as we redefine what's possible in trading, advocate for our customers, and continue our journey toward becoming the world's top retail-focused trading platform in the world.

What you'll do:

We are seeking a Sr. Software Engineer to join our Evaluation Services team. Our Evaluation Services business powers funded trader programs that give aspiring traders a pathway to professional trading capital. You will design, build, and maintain the Scala-based backend systems that power our auto-liquidation engine, risk evaluation, and trading services-the core systems our platform and partners depend on. You will own complex backend problems end-to-end and work alongside Trading Services Engineers, frontend engineers, QA, and solutions engineers to deliver high-quality, production-ready features in a fast-paced environment.

In this role you will:

• Design and implement backend services in Scala for evaluation, risk, and trading service workloads, including real-time auto-liquidation, account state management, and post-trade processing
• Build and evolve actor-based systems, such as Akka or similar technologies, that handle high-throughput market data, position changes, and event-driven workflows
• Own significant features end-to-end, from technical specifications through implementation, code review, and production handoff
• Design data models and database changes in PostgreSQL, including JSONB where appropriate, and contribute to the shared master schema, Protobuf, and SQL repositories
• Diagnose and resolve complex backend issues, including production incidents, by analyzing logs, tracing distributed flows, and reproducing edge cases under realistic loads
• Drive code quality across the team through thorough pull request reviews, clear acceptance criteria, disciplined development testing, and proper instrumentation and observability
• Collaborate with Trading Services, Solutions Engineering, and Product to translate business requirements into well-scoped, accurately estimated stories
• Contribute to architectural decisions and long-term technical debt remediation, including modernizing legacy Scala services and evaluating new event bus technologies
• Mentor junior team members on Scala idioms, functional design, testing practices, and incident response
• Develop deep expertise in NinjaTrader's evaluation platform and partner integrations to provide authoritative backend leadership

What you'll need:

• 5+ years of backend software engineering experience building production systems that handle real-time data, concurrency, and high availability
• Strong, hands‑on Scala expertise, including idiomatic Scala, functional patterns, testing with ScalaTest or similar tools, and comfort working in a large, existing Scala codebase
• Experience with actor‑based concurrency models, such as Akka, Pekko, or equivalent technologies, including an understanding of supervision, message passing, and backpressure
• Solid relational database skills with PostgreSQL, including schema design, indexing, query optimization, and sound judgment about when to use JSONB versus a normalized structure
• Comfort with event‑driven architectures, message buses such as Kafka or Pub/Sub, and asynchronous workflows
• Excellent troubleshootin