Sr. Software Engineer II, Platform/API

NinjaTrader is a retail trading platform and futures broker that provides trading software and brokerage services. The Sr. Software Engineer II will own the service layer for the Activation & Onboarding platform, designing, deploying, and operating Node.js and TypeScript services for account creation, identity verification, funding, event-driven processing, and reliable multi-step workflows.

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 is a strong plus