Senior Staff Engineer

Overview

Connecting clients to markets – and talent to opportunity With 4,300 employees and over 400,000 retail and institutional clients across more than 80 offices on five continents, StoneX is a Fortune-100, Nasdaq-listed provider connecting clients to the global markets. We focus on innovation, human connection, and delivering world-class products and services to investors worldwide. At StoneX, you’ll join an institutional-grade financial services organization building modern, high-performance digital platforms. Our teams combine cutting-edge technology, deep domain expertise, and strong engineering culture to deliver scalable and reliable trading experiences.

Responsibilities Position Purpose We are seeking a

Senior React UI Developer to design and build our next-generation

web trading platforms . This role focuses on

frontend architecture, performance optimization, and scalable UI development , working closely with backend, mobile, and platform teams. You will play a key role in shaping UI standards, reusable component systems, and frontend best practices for highly interactive, real-time trading applications.

Primary ResponsibilitiesFrontend Architecture & Development

• Web Trading Platforms + Design and develop responsive, high-performance web trading applications using React and TypeScript + Ensure consistent user experiences across browsers and devices
• Component & Design System Development + Build and maintain reusable UI components and composite components + Enforce consistent usage of design tokens and UI primitives + Promote best practices for component composition, accessibility, and maintainability
• State Management & Routing + Design scalable client-side state management strategies + Implement robust routing architectures for complex, multi-domain applications

Performance & Reliability

• Performance Optimization + Implement lazy loading, code splitting, and bundle optimization strategies + Optimize rendering performance for real-time and data-heavy UIs
• Error Handling & Observability + Implement error boundaries, logging, and monitoring for frontend applications + Improve resiliency and debuggability of UI systems

Security & Integration

• Authentication Integration + Integrate frontend applications with IDP-based authentication systems + Ensure secure handling of sessions, tokens, and user identity flows
• API Integration + Consume RESTful APIs and event-driven data streams efficiently + Collaborate with backend teams to define frontend-friendly API contracts

Collaboration & Leadership

• Cross-Functional Collaboration + Work closely with product managers, designers, backend engineers, and QA teams + Translate business and UX requirements into scalable frontend solutions
• Technical Leadership + Mentor junior and mid-level developers + Drive frontend best practices, architectural consistency, and code quality
• Stakeholder Communication + Clearly communicate technical decisions, trade-offs, and implementation approaches

Qualifications Required Qualifications To succeed in this role, you will need:

• 5+ years of professional frontend development experience
• Expert knowledge of JavaScript and TypeScript (ES6+, async programming, closures, types)
• Strong experience with React, including: + Hooks and component patterns + Lazy loading and code splitting + Error boundaries and error capturing + State management libraries + Routing architectures
• Strong understanding of frontend performance optimization techniques
• Experience integrating with authentication and authorization systems
• Solid understanding of RESTful APIs and frontend-backend integration

What Will Make You Stand Out

• Experience building trading, financial, or real-time data platforms
• Familiarity with React Native or shared web/mobile UI strategies
• Experience working within large-scale design systems
• Understanding of CI/CD pipelines and frontend build tooling
• Experience working in regulated or security-sensitive environments

Education

• Bachelor’s or Master’s degree in Computer Science, Engineering, or a related field (or equivalent practical experience)

Working Environment

• Hybrid