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Agent guide: [/agents.md](https://www.wearedevelopers.com/agents.md). --- # Senior Frontend Engineer - **Company:** London Construction Jobs - **Location:** London, UK - **Experience:** Expert - **Contract:** Permanent contract - **Skills:** Clean Code Principles, JavaScript (Programming Language), Application Programming Interfaces (APIs), User Authentication, Automation of Tests, Browser Compatibility, Continuous Integration, Identity and Access Management, OAuth, Performance Tuning, Openid Connect, TypeScript, Management of Software Versions, ReactJS, Backend, Front End Software Development - **Published:** August 15, 2026 - **Apply:** https://www.totaljobs.com/job/senior-front-end-engineer/london-stock-exchange-job107848678 ## About the Role * Proven of experience in frontend development, with deep expertise in React, TypeScript, and modern JavaScript. * Proven experience designing and maintaining SDKs or libraries used by other developers. * Strong understanding of OAuth2, OpenID Connect, and secure authentication flows. * Familiarity with CI/CD pipelines, automated testing, and versioning strategies for SDKs. * Experience with frontend performance optimization, cross-browser compatibility, and accessibility standards. * Passion for clean code, automation, and continuous improvement. * Excellent interpersonal skills and a passion for developer experience and security.ROLE PROFILE, + Proven of experience in frontend development, with deep expertise in React, TypeScript, and modern JavaScript. + Proven experience designing and maintaining SDKs or libraries used by other developers. + Strong understanding of OAuth2, OpenID Connect, and secure authentication flows. + Familiarity with CI/CD pipelines, automated testing, and versioning strategies for SDKs. + Experience with frontend performance optimization, cross-browser compatibility, and accessibility standards. + Passion for clean code, automation, and continuous improvement. + Excellent interpersonal skills and a passion for developer experience and security. ## Description We are seeking a Senior Frontend Developer to join our Customers Identity & Access Management team at LSEG. You will play a pivotal role in maintaining and evolving our JavaScript SDK, a critical interface that enables secure authentication and seamless integration of our Authentication into client applications across to our customers. This role is ideal for someone who thrives in developer experience, SDK design, and security-focused frontend engineering. What You'll be doing: * Own and maintain a JavaScript SDK built with React and TypeScript, enabling secure integration with our custom Secure Token Service. * Design intuitive, developer-friendly APIs that abstract complex authentication flows (OAuth2, OpenID Connect). * Ensure the SDK is secure, performant, and easy to integrate across a wide range of frontend applications. * Collaborate with backend engineers to align SDK functionality with evolving identity protocols and token flows. * Build automated tests and CI pipelines to ensure quality, reliability, and backward compatibility. * Write clear documentation and sample apps to support internal and external developers. * Stay current with frontend security best practices and contribute to platform-wide improvements., We are seeking a Senior Frontend Developer to join our Customers Identity & Access Management team at LSEG. You will play a pivotal role in maintaining and evolving our JavaScript SDK, a critical interface that enables secure authentication and seamless integration of our Authentication into client applications across to our customers. This role is ideal for someone who thrives in developer experience, SDK design, and security-focused frontend engineering. What You'll be doing: + Own and maintain a JavaScript SDK built with React and TypeScript, enabling secure integration with our custom Secure Token Service. + Design intuitive, developer-friendly APIs that abstract complex authentication flows (OAuth2, OpenID Connect). + Ensure the SDK is secure, performant, and easy to integrate across a wide range of frontend applications. + Collaborate with backend engineers to align SDK functionality with evolving identity protocols and token flows. + Build automated tests and CI pipelines to ensure quality, reliability, and backward compatibility. + Write clear documentation and sample apps to support internal and external developers. + Stay current with frontend security best practices and contribute to platform-wide improvements. * What You'll bring ## Related Videos - [Watch Tests Go Brrrr! : Getting Started with Cypress in ReactJS](https://www.wearedevelopers.com/videos/282-watch-tests-go-brrrr-getting-started-with-cypress-in-reactjs) - [Developing the Backend with Stefan Lingler, CTO at Shpock](https://www.wearedevelopers.com/videos/100360-developing-the-backend-with-stefan-lingler-cto-at-shpock) - [Keeping applications secure by evolving OAuth 2.0 and OpenID Connect](https://www.wearedevelopers.com/videos/100152-keeping-applications-secure-by-evolving-oauth-2-0-and-openid-connect) - [But, you're not Facebook](https://www.wearedevelopers.com/videos/378-but-you-re-not-facebook) - [Meet Your New BFF: Backend to Frontend without the Duct Tape](https://www.wearedevelopers.com/videos/682-meet-your-new-bff-backend-to-frontend-without-the-duct-tape) - [Nest.js - TypeScript in the backend can also be clean](https://www.wearedevelopers.com/videos/1033-nest-js-typescript-in-the-backend-can-also-be-clean) ## Related Articles - [The Best 7 Frontend Frameworks for Developers in 2025](https://www.wearedevelopers.com/magazine/400-the-best-7-frontend-frameworks-for-developers-in-2025) - [Frontend Developer Salary in The UK](https://www.wearedevelopers.com/magazine/233-frontend-developer-salary-in-the-uk) - [16 Best Free React UI Libraries in 2025](https://www.wearedevelopers.com/magazine/148-16-best-free-react-ui-libraries-in-2025) - [React Developer Salary [2023]](https://www.wearedevelopers.com/magazine/198-react-developer-salary-2023) - [Software Engineer Salary London](https://www.wearedevelopers.com/magazine/252-software-engineer-salary-london) - [What’s the Difference Between Frontend and Backend Development?](https://www.wearedevelopers.com/magazine/240-what-s-the-difference-between-frontend-and-backend-development)