Sr. Software Engineer I (Scala)

As a Senior Software Engineer I (Scala) at NinjaTrader, you join the Evaluation Services team to design, build, and maintain the Scala-based backend systems powering our funded trader programs. You will own complex backend problems end-to-end, working on real-time auto-liquidation engines, risk evaluation, and trading services that traders and partners depend on.

What you'll do

• 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 bring

• 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 or Pekko, 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 troubleshooting skills, with the ability to read logs, trace requests across distributed systems, and isolate root causes under pressure
• Demonstrated ability to write clear technical specifications, scope work realistically, and identify risks early
• High standards for code, tests, documentation, and pull requests, along with a willingness to uphold those standards during code reviews
• Ability to think on your feet and adapt quickly when priorities shift or unexpected issues arise
• Outstanding written and verbal communication skills, with the ability to explain backend tradeoffs to technical and non-technical audiences
• Self-starter who thrives in ambiguity and can manage multiple complex backend initiatives simultaneously

Nice to have

• Experience with trading platforms, fintech, or capital markets technology
• Understanding of trading concepts, including order routing, market data, position management, risk and liquidation logic, and profit and loss calculations
• Familiarity with Protobuf, gRPC, or schema-based service contracts
• Experience migrating or modernizing legacy Scala systems or evaluating transitions from Scala to Rust or Go
• Background in observability, including distributed tracing, structured logging, and metrics using Datadog, Google Cloud Platform, or similar technologies
• Prior experience supporting enterprise or business-to-business partner integrations

What we offer

• Salary range of $125,000 to $175,000 USD annually, plus an annual target bonus of 12% based on individual performance (50%) and company/team performance (50%)
• 401(k) plan with 3.5% company match
• 18 days of annual paid time off, plus 7 paid holidays and 5 conditional holidays
• 20 additional flex remote days annually
• 5 company-wide office-optional weeks tied to major holidays
• 1 service day annually
• Health, vision, and dental coverage
• Life and disability insurance covered 100% by NinjaTrader
• Paid parental bonding leave
• Hybrid work schedule based in Chicago, IL (Tuesday through Thursday in-office, Monday and Friday remote); remote flexibility available for exceptional candidates in select states

About NinjaTrader

NinjaTrader is an industry-leading trading platform and futures broker with over 2 million users. The company powers funded trader programs and provides award-winning software and brokerage services for traders across financial markets worldwide.