Sr. Software Engineer I, Scala

As a Sr. Software Engineer I at NinjaTrader, you will design, build, and maintain the Scala-based backend systems that power our Evaluation Services team. You own complex backend problems end-to-end, working on auto-liquidation engines, risk evaluation, and trading services that power our funded trader programs and platform partnerships. You collaborate with Trading Services Engineers, frontend engineers, QA, and solutions engineers to deliver production-ready features.

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, 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 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 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
• 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 paid time off annually plus 7 paid holidays (some positions may qualify for more)
• 20 additional flex remote days annually
• 5 company-wide office-optional weeks tied to major holidays
• 1 service day annually
• Paid parental bonding leave
• Health, vision, and dental coverage
• Life and disability insurance covered 100% by NinjaTrader
• Hybrid work schedule for Chicago-based employees: in-office Tuesday through Thursday, remote Monday and Friday

About NinjaTrader

NinjaTrader is an industry-leading trading platform and futures broker with over 2 million users, serving as the number one rated futures brokerage worldwide. The company powers funded trader programs through its Evaluation Services business, providing aspiring traders a pathway to professional trading capital, while continuously innovating to modernize the futures industry.