Senior Rust Software Engineer

About this role

About Onyx Capital Group

Onyx Capital Group is the world’s #1 liquidity provider for energy derivatives, trading over $3.2 trillion in notional value annually. Through Onyx Commodities, the Flux Terminal, and our trading division Axis, we dominate the benchmarks that matter — Dated Brent, S2F contracts, and beyond. We are not a bank. We are not a hedge fund. We are a technology-driven market-making powerhouse at the intersection of global energy markets, data, and engineering — and we are growing fast.

Engineering at Onyx

We don’t hire passengers — we hire pilots. Every engineer here takes ownership, pushes back when the design isn’t right, and holds the bar high without being asked. We practise TDD, design for observability from day one, and treat software craftsmanship as a genuine competitive advantage. The team is small, senior, and embedded directly in the trading floor. There are no layers of abstraction between you and the business — your work has immediate, measurable impact from day one.

The Opportunity

We are building our Sri Lanka engineering hub and looking for Senior Rust Software Engineers to be founding members of that team. Working alongside our global engineering organisation, you will take full ownership of complex systems end-to-end — from architecture and design through delivery and into production. Your work will power live trading infrastructure used by some of the world’s most demanding market participants.

### Requirements

• 5–10+ years in a software engineering role; track record of delivering production-quality features independently
• Deep Rust expertise — ownership, lifetimes, trait objects, unsafe code, async runtimes, and macro authorship; comfortable working at the boundary of safe and systems-level Rust in production
• Demonstrated experience building low-latency, high-throughput systems in Rust — including performance profiling, benchmarking, and architectural ownership of critical-path services
• Strong systems pr...