Sr. Software Engineer II, Platform/API

NinjaTrader is an industry-leading trading platform and futures broker focused on empowering retail traders through software and brokerage services. The Sr. Software Engineer II will own the Node.js and TypeScript service layer supporting activation and onboarding, including event-driven workflows, integrations, background processing, and reliability at scale.

Responsibilities:

• Design, develop, and maintain Node.js and TypeScript services that orchestrate account creation, identity verification, agreement handling, and funding hand-off
• Build the event-driven and asynchronous processing that moves applicant and verification data between internal systems and outside providers, using message queues, pub/sub, and streaming pipelines
• Own correctness in long-running, multi-step flows: idempotency, retry and resumption semantics, deduplication, and reconciliation for steps that cannot simply be replayed
• Design and evolve the background task runners and job orchestration that drive downstream account creation and decisioning
• Build the operational tooling the squad needs when an application stalls mid-flow: inspection of in-flight state, targeted replay, and safe requeue
• Define service-level expectations for the flows you own, along with the monitoring and alerting that surface provider failures and applicant drop-off before a customer reports them
• Design and implement scalable, resilient service architecture, using cloud-based infrastructure such as Google Cloud Platform and Kubernetes
• Extend onboarding to new markets, brands, and account types, keeping jurisdiction-specific behavior configurable rather than forked
• Coordinate technical direction with engineers on adjacent squads whose systems consume your events, and coach engineers at the Sr. Software Engineer I level through design review and pairing

Requirements:

• 6+ years of professional software development experience building and operating backend services in production
• Bachelor's or Master's degree in Computer Science, Software Engineering, or a related field (or equivalent practical experience)
• Deep Node.js and TypeScript expertise, with strong command of asynchronous patterns, concurrency, and backpressure
• Proven production experience with event-driven architecture, including delivery guarantees and poison-message handling, on message queues, pub/sub, or streaming platforms such as Kafka or Google Cloud Pub/Sub
• Demonstrated experience building idempotent, resumable workflows that stay correct under retries, partial failure, and out-of-order delivery
• Strong SQL and schema design, plus hands-on experience with Docker, Kubernetes, and a major cloud platform
• Demonstrated use of AI coding agents (Codex, Cursor, Claude Code) as a standard part of your engineering workflow, with the judgment to review and validate AI-assisted code before it ships
• Excellent communication and the ownership to run a workstream end to end: design, implement, test, deploy, operate on-call, and iterate
• Experience with identity verification, KYC/AML, or fraud and risk decisioning systems
• Experience in fintech, trading, or brokerage, particularly in a regulated financial services environment
• Experience integrating third-party providers whose contracts and failure modes you do not control
• Familiarity with workflow or saga orchestration frameworks, and with feature flagging platforms such as Statsig
• Passion for futures, derivatives, and trading technologies