Location
Paternoster Square, London

Hours
Full Time

Salary
Negotiable

About the Role
LSEG (London Stock Exchange Group) is a leading global financial markets infrastructure and data provider with a rich history spanning over 300 years. We enable businesses and economies worldwide to fund innovation, manage risk, and create jobs through our trusted financial market infrastructure services and open-access model.

We are seeking a Senior Frontend Engineer to join our Customers Identity & Access Management team. In this role, you will own and maintain a JavaScript SDK built with React and TypeScript that enables secure authentication and seamless integration of our Authentication services into client applications. This is a pivotal position focused on developer experience, SDK design, and security-focused frontend engineering.

You will design intuitive, developer-friendly APIs that abstract complex authentication flows such as OAuth2 and OpenID Connect, ensure the SDK is secure, performant, and easy to integrate, and collaborate closely with backend engineers to align SDK functionality with evolving identity protocols. Additionally, you will build automated tests and CI pipelines to maintain quality and reliability, write clear documentation and sample applications, and stay current with frontend security best practices to contribute to platform-wide improvements.

At LSEG, you will be part of a high-performing team where your expertise is valued and your impact is visible. We offer a flexible hybrid work model, access to cutting-edge tools, opportunities for continuous learning, and a collaborative culture that values technical mastery, ownership, and innovation. Join us to work on a globally critical system powering secure financial transactions across markets.

Experience
- Proven experience in frontend development with deep expertise in React, TypeScript, and modern JavaScript.
- 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.

About you
- Passionate about clean code, automation, and continuous improvement.
- Excellent interpersonal skills with a strong focus on developer experience and security.
- Motivated to work collaboratively in a diverse and inclusive environment.
- Committed to innovation and delivering high-quality solutions.

Qualifications
- Relevant technical qualifications or equivalent experience preferred but not mandatory.
- A strong commitment to learning and professional growth aligned with LSEG’s values of Integrity, Partnership, Excellence, and Change.