Staff Engineer React UI Developer

Connecting clients to markets and talent to opportunity

With 4300 employees and over 400000 retail and institutional clients across more than 80 offices on five continents StoneX is a Fortune100 Nasdaqlisted provider connecting clients to the global markets. We focus on innovation human connection and delivering worldclass products and services to investors worldwide.

At StoneX youll join an institutionalgrade financial services organization building modern highperformance digital platforms. Our teams combine strong engineering culture modern technologies and deep domain expertise to deliver scalable and reliable trading experiences

Position Purpose

We are seeking a React UI Developer (MidLevel) to contribute to the development of our nextgeneration web trading platforms. This role focuses on building highquality performant and maintainable frontend features using React and TypeScript working closely with senior frontend engineers backend teams designers and product managers.

You will contribute to reusable UI components follow established frontend architecture and standards and help deliver highly interactive realtime user experiences.

Primary Responsibilities

Frontend Architecture & Development

Web Trading Platforms

• Develop responsive highquality web trading applications using React and TypeScript
• Implement UI features following established frontend architecture and standards
• Ensure consistent user experience across modern browsers and devices
• Collaborate with senior engineers to deliver scalable and maintainable solutions

Component & Design System Development

• Build and enhance reusable UI components within an existing design system
• Apply design tokens UI primitives and accessibility standards consistently
• Follow best practices for component composition testing and maintainability
• Contribute improvements and fixes to shared component libraries

State Management & Routing

• Implement clientside state management using approved libraries and patterns
• Work with existing routing solutions for complex multifeature applications
• Understand data flow component lifecycle and statedriven UI behavior

Performance & Reliability

Performance Optimization

• Apply performance best practices such as memoization lazy loading and code splitting
• Optimize rendering behavior for dataheavy and interactive UI components
• Identify and resolve UI performance issues with guidance from senior engineers

Error Handling & Observability

• Implement basic error handling patterns including error boundaries
• Add logging and monitoring hooks according to team standards
• Help improve frontend stability and debuggability through proactive fixes

Security & Integration

Authentication Integration

• Integrate frontend applications with existing authentication and identity solutions
• Follow secure patterns for handling sessions tokens and authenticated flows
• Adhere to security and compliance requirements defined by platform teams

API Integration

• Consume RESTful APIs and realtime data streams efficiently
• Handle loading states error conditions and partial data scenarios gracefully
• Collaborate with backend engineers to clarify API usage and constraints

Collaboration

CrossFunctional Collaboration

• Work closely with product managers designers backend engineers and QA teams
• Translate UX and business requirements into frontend implementations
• Participate actively in sprint planning refinement and reviews

Team Contribution

• Participate in code reviews to maintain code quality and consistency
• Communicate progress risks and technical questions clearly
• Continuously improve frontend skills and understanding of the product domain

Required Qualifications

To succeed in this role you will need:

• 24 years of professional frontend development experience
• Strong knowledge of JavaScript and TypeScript (ES6 async programming)
• Handson experience with React including:
• Functional components and hooks
• Component composition and reuse
• Basic performance optimization techniques
• Experience with clientside state management and routing solutions
• Solid understanding of RESTful APIs and frontendbackend integration
• Familiarity with frontend testing debugging and code review practices

What Will Make You Stand Out

• Experience working on dataintensive or realtime web applications
• Familiarity with design systems and reusable component libraries
• Exposure to financial trading or regulated environments
• Experience with frontend build tooling and CI/CD pipelines
• Strong attention to UI quality performance and user experience

Education

• Bachelors or Masters degree in Computer Science Engineering or a related field
  (or equivalent practical experience)

Working Environment

• Hybrid