We are recruiting on behalf of our client, a leading technology company at the forefront of online privacy and security. They are seeking a Senior Browser Extension Engineer to join their growing team, working on high-performance browser extensions that integrate seamlessly into their ecosystem. This is an exciting opportunity to work on complex engineering challenges, influence key technical decisions, and develop innovative solutions that impact millions of users worldwide. Key Responsibilities Extension Development Architect and develop robust, high-performance browser extensions using TypeScript, React, and modern frontend tooling. Design scalable, well-structured solutions to complex technical challenges. Debug and reverse-engineer unfamiliar code to diagnose and resolve issues efficiently. Drive performance optimisations, enhance UI responsiveness, and streamline event handling. Ensure fault-tolerant integrations that adapt to diverse website implementations. Collaboration & Integration Work closely with engineers, designers, and product teams to align browser extension functionality with app and web platforms. Provide technical leadership in cross-functional discussions, guiding feasibility and architectural decisions. Partner with support and QA teams to diagnose and resolve technical issues. Mentor junior engineers and enforce high technical standards through thorough code reviews. Security & Privacy Develop privacy-first features, ensuring secure handling, storage, and transmission of sensitive data. Advocate for secure coding practices and proactively mitigate security risks. Apply fundamental browser security principles to protect user data. Testing & Quality Assurance Improve test coverage for internal npm packages, writing unit and integration tests. Shape the automated testing strategy, exploring regression testing for browser extensions. Monitor and enhance extension performance to ensure a seamless user experience. Key Skills & Experience 5 years of commercial experience with TypeScript and React, including advanced TypeScript features. Strong JavaScript expertise, including asynchronous programming, closures, and functional patterns. In-depth knowledge of browser extension architecture and APIs. Experience with Redux, Webpack, Jest, and other front-end tools to maximise performance and scalability. Strong debugging skills and ability to resolve complex technical issues. Passion for software craftsmanship, mentoring, and driving best practices. Whats on Offer? Our client values their employees and offers an exceptional benefits package, including: Salary: £50,000 - £60,000 up to 10% annual performance-based bonus 28 days annual leave ( additional accrual for length of service) Private healthcare & dental care (BUPA) Pension scheme Netflix & Spotify subscriptions Gym & Golf Membership Onsite bar, beer fridges & cocktail lounge Onsite hairdressers Company-funded meals, snacks & drinks Regular company events & social activities This is a fantastic opportunity to join a cutting-edge company that values innovation and technical excellence. If you have the skills and experience required, apply now This is an office based role in Segnesworth ADZN1_UKTJ