Senior React.js Developer

BettingJobs is working with a fast-growing platform operating in high-volume, regulated payment environments, looking for a Senior React.js Developer to help build and scale its customer-facing and back-office applications. This is a genuine opportunity to take ownership of complex, high-traffic frontend architecture within a business that's investing heavily in product, security and data.
The role would suit an experienced React specialist who thrives on technical challenge and wants exposure to real payment flows, third-party integrations and secure, high-transaction systems. You'll work closely with Product, UI/UX, Backend, DevOps and QA to deliver polished, performant applications, while mentoring junior and mid-level developers and helping shape frontend best practice across the team.

Responsibilities:

• Design, build and maintain scalable, high-performance applications using React.js, with reusable, well-tested components and architecture
• Translate UI/UX designs into responsive, user-friendly interfaces
• Integrate frontend applications with REST APIs and third-party services, including payment providers, wallets, banking, KYC and authentication
• Collaborate with backend teams (Java, C#) and work with real-time technologies such as WebSockets where required
• Implement secure frontend practices around authentication, authorisation and API communication
• Optimise performance, load times and browser compatibility, and work within Docker-based development environments
• Partner with DevOps on CI/CD and deployment, troubleshoot production issues, and contribute to architecture discussions and code reviews
• Mentor junior and mid-level developers

Requirements:

• 7+ years' professional development experience with strong hands-on React.js expertise, plus JavaScript/TypeScript, HTML5/CSS3 and component-based architecture
• Strong grasp of modern React (Hooks, Context API, state management, performance optimisation, lazy loading/code splitting) and tools such as Redux, Redux Toolkit or Zustand
• Experience with frontend testing (Jest, React Testing Library, Playwright)
• Solid Node.js experience, with strong understanding of RESTful APIs, JSON, JWT/OAuth2 and API security
• Previous experience in Payments, Banking, FinTech or similar high-transaction environments, including deposit/withdrawal flows, payment provider integrations, webhooks and transaction status handling
• Advantageous: KYC/AML or identity verification integrations, microservices architecture, Kubernetes, AWS/GCP/Azure, OWASP knowledge, and experience with iframe-based or embedded applications