Remote Senior Frontend Engineer

Remote (UK-based) | Full-Time

Reactive Markets is the 2026 OTC Trading Platform of the Year (). Our network handles over $50 billion in daily trading volumes across FX, Equities, and Cryptocurrency, connecting 40+ 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.

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 Type Script 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.

• Complex full-stack features in Type Script 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, Web Sockets, 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

Technical:

• Strong full-stack engineering ability with deep Type Script / JavaScript (ES6+) (5+ years)

• Solid experience with React and reactive state management (RX, MobX, or similar)

• Real working ability in Rust — it's part of our stack and not optional at this level. If your Rust is still developing, a strong track record of picking up new languages to depth quickly is essential

• Strong grasp of distributed systems, API design, and real-time data (REST, Web Sockets, 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. You're delivery-focused — you iterate, you improve, you get things into production

• You run with things. Give you an ambiguous, complex problem and you drive it to done without being managed through it. Senior here means trusted, not just experienced

• You have range. You're not just strong in the familiar parts of the stack — you pick up the unfamiliar and hold your own on the hardest work

• You own it. When…