Senior Full Stack Engineer – JavaScript / TypeScript

Senior Software Engineer – JavaScript/TypeScript Overview 🏢 Company | Financial markets technology 👤 Position | Senior Software Engineer – JavaScript/TypeScript 🎯 Impact | Build the applications used to operate, monitor and control high-performance trading technology 🌟 Core Technology | TypeScript, JavaScript, React, Python APIs, data-driven front-end architecture 📍 Location | London 💻 Hybrid | Minimum 3 days a week in the office 💰 Offer | Up to £100,000 + discretionary bonus 💎 Benefits | 25 days’ holiday plus bank holidays, private medical insurance, pension, life assurance, income protection, critical illness cover, enhanced parental leave, flexible working hours, electric car scheme and workplace nursery scheme The Role Most React engineering jobs focus on customer-facing products. This one helps power technology used by financial markets around the world. Here, you’ll build applications that help people trade on, monitor and control technology used across financial markets. You'd be building the webapps and desktop tools that traders and market operators use to trade on, monitor, and control exchange infrastructure, technology that doesn't just run here, it's licensed out and run by other markets too. Every screen you ship carries weight. You’ll get ownership rather than a tightly defined list of tickets. Working with product, infrastructure, QA and UX, you’ll help shape the technical approach, challenge weak ideas and turn wireframes into reliable applications. You’ll also influence how the team builds software. That includes reviewing designs, improving engineering standards and supporting less experienced developers without becoming a full-time manager. The company develops technology for regulated financial markets. You don’t need previous trading experience, but you should enjoy solving technically complex problems where poor performance or unreliable code has a visible consequence. What You’ll Build You’ll design and develop scalable applications and APIs using JavaScript, TypeScript and React. Your work will include: Building responsive, data-intensive web and desktop applications.Integrating frontend applications with Python-based APIs.Improving performance, accessibility, security and automated test coverage. You’ll also contribute to technical reviews, CI/CD improvements and decisions around new tools, architecture and engineering practices. What You’ll Need You’ll be a strong match if you have: At least five years of frontend development experience, with strong commercial JavaScript, TypeScript and React knowledge.Experience building data-driven applications where performance, reliability and usability are important.A solid understanding of automated testing, including unit, integration and end-to-end testing. You should also be comfortable working with HTML5, CSS3, responsive design, browser compatibility and Linux or WSL development environments. You don’t need to be a Python engineer, but you’ll work closely with Python APIs, so some familiarity will help. Experience with cloud platforms, Infrastructure as Code, containerised applications or financial markets technology would be useful, but none of these is essential. The broader technical team uses: JavaScript, TypeScript, React, Python, WSL/Linux, CI/CD pipelines, cloud infrastructure and IaC. How The Team Works You’ll report to a Lead Software Engineer and join a team that values practical ideas, shared ownership and direct communication. People are trusted to make decisions, but you won’t be left to struggle alone. The team reviews work openly, shares technical knowledge and expects senior engineers to raise standards rather than protect their own corner. The London team works together in the office for at least three days each week, with the remaining time available for home working. 📅 Interview Process | Full process shared during the initial confidential conversation. Click Apply to receive the full briefing and arrange a confidential discussion about the team, technology and work you’d be taking ownership of.