Senior Backend Engineer (Node.js / TypeScript)

Responsibilities

• Market data: ingest vendor feeds, normalize instruments and symbology, and fan out to web and mobile clients over WebSockets (subscription management, snapshot + delta, conflation and throttling, slow-consumer handling, reconnect and resync); enforce entitlements (real-time vs. delayed, professional vs. non-professional).
• Order management: build the integration layer on top of the clearing firm's REST and FIX APIs — order gateway (validation, pre-trade checks, idempotent submission), order state driven by provider events, positions, realized and unrealized P&L, reconciliation against snapshots and the ledger.
• Reliable ingestion of provider webhooks and event streams: signature verification, deduplication, out-of-order handling, gap detection, replay.
• Authentication and session management, account lifecycle, entitlements, and billing hooks.
• Identify gaps in vendor APIs and propose solutions (build, work around, or escalate to the vendor). Design for graceful degradation when upstream feeds are unavailable.

Requirements

• 5+ years of backend development with a focus on distributed, event-driven systems; 3+ in Node.js / TypeScript, including the runtime under load (event loop, stream backpressure, memory/GC, scaling stateful connections).
• Has built and operated a high fan-out real-time system serving many concurrent clients and can describe it in numbers (connections, messages per second, p99 latency).
• Practical understanding of message ordering, duplicate delivery, idempotency, retries, backpressure, replay, and failure recovery.
• Experience running production systems that handle financial transactions; experience with monitoring, structured logging, tracing, and incident investigation.
• Experience with AWS (containers, IAM, managed messaging/streaming) and Redis; infrastructure-as-code.
• Strong automated-testing practices (unit, integration, end-to-end).
• Occasional traveling to the USA might be needed. 

Nice to have

• Brokerage, clearing, custody, or market-data provider integrations; knowledge of equity and options order lifecycles (submission, partial fills, cancel/replace, rejection).
• FIX, financial instrument symbology, exchange connectivity.
• PostgreSQL, Redis, and a time-series or analytical store.
• Systems handling monetary values, audit trails, reconciliation, regulatory requirements.
• Futures, crypto, or prediction-market platforms.