Senior Frontend Engineer

About this role

SENIOR FRONTEND ENGINEER Remote (UK-based) | Full-Time ABOUT US Reactive Markets is the 2026 OTC Trading Platform of the Year (Risk.net http://Risk.net). Our network handles over $75 billion in daily trading volumes across FX, Equities, and Cryptocurrency, connecting 60+ of the world's leading liquidity providers. We build trading systems that operate at the edge of what's technically possible — where nanoseconds matter and a dropped message costs real money.

Our engineering team is small, senior, and deeply invested in the craft of building cutting edge, reliable, high-performance systems. THE ROLE We're looking for a senior full-stack engineer to build the trading platform our clients use every day. Despite the "frontend" name, this is not a UI-only role — our Frontend team works across the whole application stack in TypeScript and Rust, from the trader-facing interfaces down to the services behind them.

It's distinct from our Backend team, who own the low-latency C++/Go trading engine. This is a senior individual contributor role for someone who takes on the hardest problems and delivers them under their own steam. You'll own complex, ambiguous, performance-critical work end-to-end — designed, built, tested, deployed, and supported in production. You lead through code, craft, and mentoring, setting the technical example the rest of the team calibrates to.

This is not a role where you write code and throw it over a wall: our engineers own the full lifecycle, and when something breaks, you're part of the team that investigates and fixes it. Occasional hours outside the normal working day are required for production releases, scheduled maintenance windows, and Level 3 support during critical incidents. We keep this to a minimum and recognise the commitment — but owning a production trading platform means being there when it matters.

WHAT YOU'LL WORK ON - Complex full-stack features in TypeScript and Rust — from trader-facing interfaces to the application services behind them - Real-time market-data presentation and high-throughput, low-latency application code across FX, Equities, and Cryptocurrency - React and reactive state management (RX, MobX, or similar) for demanding, data-dense trading interfaces - Distributed systems and real-time data over REST, WebSockets, and network protocols - Architecture and solution design for the hardest technical problems the team faces - Observability and monitoring — dashboards, alerting, and metrics that make frontend behaviour visible - Production systems that handle real money — reliability is not optional WHAT WE NEED Technical: - Strong full-stack engineering ability with deep TypeScript / JavaScript (ES6+) (5+ years) - Solid experience with React and reactive state management (RX, MobX, or similar) - Working knowledge of Rust, or the clear appetite and ability to get there — it's part of our stack - Strong grasp of distributed systems, API design, and real-time data (REST, WebSockets, network protocols such as TCP/UDP and binary protocols) - Comfortable reasoning about architecture and making defensible technical trade-offs - Python for scripting, automation, and tooling is a bonus - Git and Linux fundamentals - Experience in financial services or trading technology is a plus but not essential How you work: - You ship.