# Senior Frontend Engineer

**Company**: London Stock Exchange Group (LSEG)
**Location**: London
**Work arrangement**: hybrid
**Experience**: senior
**Job type**: full-time
**Category**: Engineering
**Industry**: Finance

**Apply**: https://lseg.wd3.myworkdayjobs.com/en-US/Careers/job/GBR-London-10-Paternoster-Square/Senior-Frontend-Engineer_R0117658-1?utm_source=yubhub.co&utm_medium=jobs_feed&utm_campaign=apply
**Canonical**: https://yubhub.co/jobs/job_72c9413e-0b0

## 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.

Responsibilities:

- 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.

Requirements:

- Proven 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.

Benefits:

- Competitive compensation with performance-based rewards.

- A flexible hybrid work model that supports work-life balance.

- Access to cutting-edge tools and infrastructure to do your best work.

- Opportunities for continuous learning, including certifications, conferences, and internal mobility.

- A collaborative culture that values technical mastery, ownership, and innovation.

- The chance to work on a globally critical system that powers secure financial transactions across markets.

## Skills

### Required
- React
- TypeScript
- JavaScript
- OAuth2
- OpenID Connect
- CI/CD pipelines
- automated testing
- versioning strategies
- frontend performance optimization
- cross-browser compatibility
- accessibility standards

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Source: [Apply at lseg.wd3.myworkdayjobs.com](https://lseg.wd3.myworkdayjobs.com/en-US/Careers/job/GBR-London-10-Paternoster-Square/Senior-Frontend-Engineer_R0117658-1?utm_source=yubhub.co&utm_medium=jobs_feed&utm_campaign=apply)