Sr. Backend Engineer - RT & Event-Driven Systems

We are Australia’s first and only personal aviation, operating in a mission-critical, real-world domain where software decisions directly impact live flight operations, passengers, and crew. 

We are 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 is for engineers who design systems around events, state transitions, and concurrency. 

The Role: 

As a Senior Backend Engineer – Real-Time & Event-Driven Systems, you will design and build the backend foundation for: 

1. Real-time, low-latency chat (presence, delivery guarantees, ordering, fan-out) 
2. Event-driven flight operations systems (flight lifecycle events, operational triggers, rule engines) 

You will architect systems where events are first-class citizens, not side effects. 

Core Responsibilities: 

Real-Time Systems (Primary) 

• Architect and build high-concurrency real-time chat using WebSockets (Socket.IO / ws) 
• Implement: 
• Presence & online state 
• Typing indicators 
• Read / delivery receipts 
• Message ordering & idempotency 
• Resilience to disconnects and reconnects 
• Ensure sub-second latency, deterministic behavior, and graceful degradation under load 
• Design chat systems that remain correct under: 
• Network jitter 
• Partial failures 
• Client reconnections 
• Horizontal scaling 

Event-Driven Architecture (Primary) 

• Design event-driven backend systems to support real-world flight operations, including: 
• Flight lifecycle events (scheduled → boarding → departed → landed → completed) 
• Operational triggers (delays, cancellations, seat changes, crew actions) 
• Time-based and rule-based automation 
• Build event pipelines using Redis Streams / PubSub and/or message brokers (RabbitMQ, Kafka) 
• Model business logic as state machines, not procedural flows 
• Ensure: 
• Event ordering guarantees 
• Idempotent consumers 
• Replayability and auditability 
• Clear separation between command, event, and read models 

Backend Engineering 

• Build clean, scalable backend services using NestJS + TypeScript 
• Design PostgreSQL schemas optimized for event sourcing, auditing, and temporal data 
• Use Redis for: 
• High-throughput messaging 
• Distributed coordination 
• Ephemeral state 
• Write explicit, testable business logic—not implicit side effects 
• Own performance, reliability, and correctness 

Required Technical Experience & Stack: 

You must have demonstrable experience in real-time and/or event-driven systems. 

Mandatory 

• 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 experience (schema design, performance, concurrency) 
• Strong Redis experience (Streams, Pub/Sub, caching, coordination) 
• Experience designing systems for high concurrency and partial failure 

Strongly Preferred (High Signal) 

• Experience with message brokers (RabbitMQ, Kafka, or similar) 
• Experience modeling business logic as state machines 
• Experience with idempotency, retries, and exactly-once / at-least-once semantics 
• Experience debugging race conditions and distributed timing issues 
• Prior work on mission-critical or real-world systems (finance, logistics, aviation, healthcare, payments) 

Testing & Quality Expectations: 

• Write deterministic tests for event-driven logic 
• Use Jest for unit and integration testing 
• Understand why testing event-driven systems is harder than CRUD—and know how to do it correctly 
• Design systems that are observable and debuggable in production 

Required Soft Skills: 

• Clear, precise written English 
• Solid spoken English—able to reason about complex systems verbally 
• High ownership and accountability 
• Comfortable working independently on ambiguous, high-impact problems 
• Thinks in systems, not just tickets