Senior React Engineer

Senior React Engineer - £700 - £800 p/day – On-site (Central London)
 
Overview
We are hiring a Senior React Engineer to join a high-performance technology team within a leading financial services organisation operating in the oil and energy derivatives space. The business runs a cutting-edge electronic trading platform that serves both internal trading teams and external clients, offering low-latency, highly reliable trading access via a modern UI.
 
We are looking for a self-starter who takes ownership of technical challenges and delivers robust solutions, with the ability to work under pressure in a fast-moving trading environment. You must also be a collaborative team player who communicates clearly and contributes to a high-quality engineering culture.
 
Role & Responsibilities

Design, build, and maintain a React/TypeScript trading UI, delivering real-time streaming data and a seamless user experience
Integrate the UI with RESTful and streaming APIs (built in Rust and Python)
Own performance improvements across dashboards, widgets, and live data visualisation
Collaborate with QA and DevOps to enhance automated testing and deployment pipelines
Lead efforts in securing, scaling, and monitoring the frontend environment
Use observability tools (Prometheus, Grafana, Loki) to monitor UI health and performance
Drive UI architectural decisions, performance benchmarking, and best practice implementation 
Essential Skills and Experience

Degree in Computer Science, Engineering, or a related field
5+ years of experience in frontend/UI engineering, with a focus on performance and scale
Deep expertise in React, TypeScript, and JavaScript
Strong understanding of WebSocket integration, low-latency data streaming, and threading
Experience troubleshooting data-heavy UIs and optimising load times
Familiarity with tools like Redis, Kafka, and cloud platforms such as Azure or AWS
Proficient in Git and modern source control workflows
Knowledge of performance diagnostics (e.g. Google PageSpeed Insights) and responsive UI optimisation 
Desirable Skills and Experience

Experience deploying apps to the Apple App Store
Knowledge of web security best practices and cyber threat mitigation
Familiarity with microservices and REST API architecture
Exposure to Infrastructure as Code tools (e.g. Terraform)
Experience working with real-time trading or data visualisation platforms 
Package:

Initial 6 month contract (high possibility of extension)
Up to £800 p/day (dependent on level of experience)
On-site (Central London)