Role purpose

You'll build the user interfaces for a multi-year programme modernizing a large portfolio of middle-office applications and moving them to AWS. This is a hands-on senior development role. You'll build data-heavy, real-time ReactJS/TypeScript applications that replace legacy desktop and web UIs. You'll own front-end integration with back-end services over REST APIs, WebSockets and Server-Sent Events (SSE). You'll also set front-end standards and tooling for the team, and use AI coding tools as part of your everyday work.

Key responsibilities

Front-end development

• Design and build complex ReactJS/TypeScript applications for trade processing, reconciliation, settlement and operations monitoring users.
• Build high-performance, data-heavy UIs: large grids (e.g. AG Grid), virtualised lists, filtering, dashboards and live status views.
• Design reusable component libraries, state management (e.g. Redux Toolkit, Zustand, React Query) and accessible, consistent UI patterns.
• Write clean, modern JavaScript (ES6+) and strongly typed TypeScript, and keep API contracts type-safe.
• You will have decent experience of understanding and changing Java backend code

Real-time and API integration

• Integrate with server-side services over REST APIs, including authentication, pagination, caching, retries and error handling.
• Build robust WebSocket clients (native WebSocket, STOMP or Socket.IO) for two-way, low-latency updates. Handle reconnects, heartbeats, back-pressure, message ordering and subscription management.
• Implement SSE streams for one-way server push (e.g. job status, cycle progress, alerts), including reconnection and event replay.
• Choose the right pattern (REST, WebSocket or SSE) for each use case, working with back-end engineers on message design and contracts.
• Make real-time screens perform well under heavy update volumes: batched rendering, memoisation and throttling.

Build tooling and quality

• Set up and maintain front-end builds with npm/pnpm and Vite, including workspaces/monorepos, dependency management, environment configuration and bundle optimisation.
• Work with DevOps on CI/CD pipelines (Harness/GitHub Actions) for front-end build, test and deployment.
• Write unit, component and end-to-end tests (Vitest/Jest, React Testing Library, Playwright or Cypress), and use mock servers for REST, WebSocket and SSE testing.
• Handle front-end security: SSO/MFA integration, token handling, XSS/CSRF protection and dependency vulnerability scanning.

AI-assisted development

• Use GitHub Copilot, Claude Code and/or Devin to speed up component building, refactoring, test generation and legacy UI analysis.
• Review all AI-generated code for correctness, accessibility, performance and security before merging.

Leadership

• Set front-end standards, review code and mentor other developers.
• Work with business analysts and users to turn legacy screens and workflows into modern, usable interfaces.
• Support releases, cutovers and early-life support.

Required experience and skills

• 8+ years in software development, with 5+ years building production ReactJS applications.
• ReactJS: expert in hooks, context, component design, performance tuning and state management.
• TypeScript/JavaScript: strong in TypeScript (generics, typing API contracts) and modern JavaScript, including async patterns.
• Build tooling: practical experience with npm, pnpm and Vite (including migrating from Webpack or similar).
• WebSockets: strong experience building and supporting production WebSocket integrations, including reconnection and state recovery.
• SSE: practical experience using Server-Sent Events/EventSource for streaming updates.
• REST APIs: strong experience consuming and designing contracts with server-side services (OpenAPI/Swagger).
• Decent Java knowledge
• Testing: Jest/Vitest, React Testing Library and an end-to-end framework.
• Git, CI/CD and agile delivery.
• Regular use of AI coding assistants in professional delivery.

Preferred

• Working knowledge of Java/Spring Boot back ends (e.g. Spring WebSocket/STOMP, SSE endpoints), to work well with back-end teams.
• Experience with Kafka-backed real-time UIs or streaming gateways.
• Experience replacing legacy UIs (GWT, PowerBuilder, desktop/Citrix applications).
• Experience in financial services, ideally trading, settlement or operations monitoring.
• Familiarity with AWS front-end hosting (S3/CloudFront, API Gateway WebSockets).

Success measures (first 12 months)

• Delivered production front ends for modernized applications, on schedule.
• Real-time features are stable under production load, with reliable reconnection and no data loss for users.
• Shared component library and front-end standards adopted across the team.
• Faster, smaller builds and good test coverage, measured against a baseline.
• Measurable productivity gains from AI tools, with no drop in quality.

About State Street

Across the globe, institutional investors rely on us to help them manage risk, respond to challenges, and drive performance and profitability. We keep our clients at the heart of everything we do, and smart, engaged employees are essential to our continued success.

We are committed to fostering an environment where every employee feels valued and empowered to reach their full potential. As an essential partner in our shared success, you’ll benefit from inclusive development opportunities, flexible work-life support, paid volunteer days, and vibrant employee networks that keep you connected to what matters most. Join us in shaping the future.

As an Equal Opportunity Employer, we consider all qualified applicants for all positions without regard to race, creed, color, religion, national origin, ancestry, ethnicity, age, disability, genetic information, sex, sexual orientation, gender identity or expression, citizenship, marital status, domestic partnership or civil union status, familial status, military and veteran status, and other characteristics protected by applicable law.

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