Sr. Software Engineer I, Evaluation Services (Scala)

NinjaTrader•Chicago, IL

6d•Hybrid

About The Position

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. In this role, 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 our 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.

Requirements

5+ years of backend software engineering experience building production systems that handle real-time data, concurrency, and high availability
Strong, hands-on Scala expertise—idiomatic Scala, functional patterns, testing (ScalaTest or similar), and comfort working in a large existing Scala codebase
Experience with actor-based concurrency models (Akka, Pekko, or equivalent)—understanding of supervision, message passing, and back-pressure
Solid relational database skills with PostgreSQL—schema design, indexing, query optimization, and judgment on when JSONB is appropriate vs. when a normalized structure is correct
Comfort with event-driven architectures, message buses (Kafka, Pub/Sub, or similar), and asynchronous workflows
Excellent troubleshooting skills with the ability to read logs, trace requests across distributed systems, and isolate root cause under pressure
Demonstrated ability to write clear technical specs, scope work realistically, and flag risk early
High-quality standards for code, tests, documentation, and PRs—and willingness to enforce the same standards in code review
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 translate backend tradeoffs for both technical and non-technical audiences
Self-starter who thrives in ambiguity and can manage multiple complex backend efforts simultaneously

Nice To Haves

Experience with trading platforms, fintech, or capital markets technology
Understanding of trading concepts: order routing, market data, position management, risk and liquidation logic, and P&L calculation
Familiarity with Protobuf, gRPC, or schema-based service contracts
Experience migrating or modernizing legacy Scala systems or evaluating Scala → Rust/Go transitions
Background in observability: distributed tracing, structured logging, and metrics (Datadog, GCP, or similar)
Prior experience supporting enterprise or B2B partner integrations

Responsibilities

Design and implement backend services in Scala for evaluation, risk, and trading services workloads—including real-time auto-liquidation, account state management, and post-trade processing
Build and evolve actor-based systems (Akka or similar) that handle high-throughput market data, position changes, and event-driven workflows
Own significant features end-to-end: from technical spec through implementation, code review, and production hand-off
Design data models and database changes (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 load
Drive code quality across the team: thorough PR reviews, clear acceptance criteria, dev-testing discipline, and proper instrumentation and observability
Collaborate with Trading Services, Solutions Engineering, and Product to translate business requirements into well-scoped, well-estimated stories
Contribute to architectural decisions and long-term tech-debt remediation, including modernization of legacy Scala services and evaluation of 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