Sr. Software Engineer II, Platform/API

NinjaTrader•Chicago, IL

2d•$140,000 - $190,000•Hybrid

About The Position

NinjaTrader is investing in the platform that takes a prospective trader from initial sign-up to funded and trading, on a modern Node.js and TypeScript service architecture. We're hiring a Sr. Software Engineer II to own the service layer it runs on. You'll own how those services are designed, deployed, and operated: event-driven orchestration, background processing, third-party integrations, and the reliability engineering that keeps a multi-step flow dependable at scale. As a senior engineer on the Activation & Onboarding squad, your work will significantly impact account approvals, time-to-funding, and how quickly we can open the platform to new markets.

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

Nice To Haves

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

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