Senior Backend Engineer

Senior Backend Developer – Real-Time & Event-Driven Systems (Independent contractor)

Company: A leading personal aviation company based in Australia, operating in a mission-critical domain where software decisions directly impact live flight operations, passengers, and crew.

Our client building real-time, event-driven backend systems that must be fast, deterministic, and fault-tolerant — supporting live chat, flight lifecycle events, operational workflows, and time-sensitive notifications with zero ambiguity.

This role is not for CRUD-centric backend developers. It's for engineers who design systems around events, state transitions, and concurrency.

What You'll Do:

You'll design and build the backend foundation for real-time, low-latency chat (presence, delivery guarantees, ordering, fan-out) and event-driven flight operations systems (lifecycle events, operational triggers, rule engines). You'll architect systems where events are first-class citizens, not side effects.

This includes building high-concurrency real-time chat using WebSockets with presence, typing indicators, read/delivery receipts, message ordering, idempotency, and resilience to disconnects. You'll also design event-driven systems for flight lifecycle management (scheduled → boarding → departed → landed → completed), operational triggers, and time/rule-based automation using Redis Streams, Pub/Sub, or message brokers like RabbitMQ or Kafka. Business logic is modeled as state machines, not procedural flows.

On the backend engineering side, you'll build clean, scalable services using NestJS + TypeScript, design PostgreSQL schemas optimized for event sourcing and temporal data, and leverage Redis for high-throughput messaging and distributed coordination.

Requirements:

• 4+ years building backend systems with TypeScript / Node.js
• Strong production experience with NestJS
• Proven experience building real-time systems using WebSockets
• Deep understanding of event-driven architecture
• Strong PostgreSQL skills (schema design, performance, concurrency)
• Strong Redis experience (Streams, Pub/Sub, caching, coordination)
• Experience designing for high concurrency and partial failure
• Clear, precise written and spoken English
• High ownership, comfortable working independently on ambiguous problems

Strongly Preferred:

• Experience with message brokers (RabbitMQ, Kafka)
• State machine modeling for business logic
• Idempotency, retries, exactly-once / at-least-once semantics
• Debugging race conditions and distributed timing issues
• Prior work on mission-critical systems (finance, logistics, aviation, healthcare, payments)