Senior Backend Developer

Java · Kotlin · Spring · GraphQL

Belgrade, Serbia · Hybrid (office + remote) · Full-time

What we build

Navixy is a programmable IoT infrastructure – think AWS, but for telematics. Our platform processes billions of data points from millions of devices, serving 700+ System Integrators and 30,000+ organizations across 130 countries. Developers use our APIs and tools to build their own fleet management, cold-chain monitoring, and field operations products.

The core platform handles real-time ingestion of binary IoT protocols, event-driven processing (IoT Logic), an analytics data layer (IoT Query), and a developer-facing UI – what we call Composable Telematics. We're now expanding this to be consumable not just by human developers, but by their AI agents – building toward APIs and tooling that are agent-ready from day one.

What you'll work on

This isn't a maintenance role. You'll be building new products and scaling systems that handle high-throughput IoT data.

• IoT Logic – the hot-path event processing engine. Binary protocol parsing from 1,600+ device types, rule evaluation, and real-time alerting at scale.

• IoT Query – our analytics and data access layer. Design and build GraphQL APIs over multi-tenant PostgreSQL, with ClickHouse for heavy analytical workloads. Think: SQL generation, security-barrier views, Bronze → Silver → Gold data pipelines.

• Platform APIs – evolve and optimize GraphQL/REST APIs under load. Backward-compatible schema evolution, caching strategies, query performance tuning.

• Infrastructure – Kubernetes-orchestrated microservices, Kafka event bus, multi-tenant data isolation. You own the reliability and performance of your services end to end.

Who you are

You're a senior backend engineer with deep JVM experience (Java/Kotlin, Spring) who's built and operated services at scale. We won't list obvious things – if you've done this work, you know what "strong SQL" and "distributed systems" mean.

What actually matters to us:

• You've owned systems, not just written code for them. You've made architectural trade-offs, debugged production under pressure, and lived with the consequences of your design decisions.

• You think of APIs as products. You care about schema design, backward compatibility, and developer experience – not just "it works."

• AI fluency at three levels: AI assistants are part of your daily workflow, not an experiment. You can scope and decompose tasks for autonomous agent execution. And you design APIs that agents can consume, not just humans.

• You communicate clearly in English (B2+). Docs, code reviews, async collaboration with a distributed team.

Tech stack

Java 11+ · Kotlin · Spring Boot · GraphQL · PostgreSQL · ClickHouse · Kafka · Kubernetes · Docker

Experience with IoT protocols, binary data parsing, or multi-tenant architectures is a bonus – but we'd rather have someone who learns fast than someone who ticks every box.

What we offer

• Compensation – competitive base salary + quarterly bonuses tied to delivery milestones. No vague "performance reviews" – you'll know the structure upfront
• Work model – hybrid in Belgrade: office for collaboration days, remote for focus work
• Growth – conference budget, internal tech talks, direct exposure to product and architecture decisions
• Health – private health insurance, paid vacation, wellness benefits
• Team – international, engineering-driven company. Your code ships to 130 countries.

If you want to build infrastructure that hundreds of companies depend on – not just maintain someone else's CRUD app – let's talk.

DM our hiring team directly or send a note to [email protected] with a few lines about what you've built and what interests you here. No cover letter needed – we'd rather see your GitHub or a project you're proud of.