Top Senior Front End Developer Jobs in Los Angeles, CA

Own the frontend platform powering Relativity Space’s operator UI, including the application shell, design system, shared data layer, and modular architecture. Lead consolidation of multiple frontends, support high-rate hardware telemetry rendering, establish frontend technical standards, and mentor engineers. The role requires deep TypeScript and React expertise, performance optimization for data-intensive applications, scalable state management, and cross-team architectural leadership.

Build and own a React and three.js real-time 3D rendering layer for browser-based mission software. Render spacecraft, orbits, sensor volumes, live telemetry, and mission data at trusted frame rates. Translate design concepts into polished front-end components and interactions, manage 3D scenes, shaders, lighting, cameras, and level of detail, and prototype visual experiences. Collaborate with data and platform engineers while owning work from prototype through production, including performance and visual quality.

Develop and maintain a fraud-analysis web application and platform, with 60–70% frontend focus. Build APIs, collaborate with product and cross-functional teams, write automated tests, analyze product metrics, troubleshoot issues, maintain service-level requirements, and participate in on-call support. The role uses React, backend languages, databases, Docker, and AWS technologies in a remote U.S.-based environment.

Lead frontend technical strategy for Affirm’s checkout decision orchestration systems. Design and architect scalable web applications, guide major technical initiatives, improve reliability and operational processes, establish engineering quality standards, collaborate with product, design, and analytics, and mentor engineers. The role focuses on building fast, clear, and reliable checkout experiences using modern declarative UI frameworks.

Build and deliver complex front-end software across the full lifecycle, including architecture, implementation, testing, deployment, monitoring, and maintenance. Develop reusable UI components and processes for data-rich advertising products, collaborate with product and design teams, lead complex technical projects, mentor engineers, participate in hiring, and use data to evaluate operational impact.

Lead frontend engineering for Nominal’s Growth & Monetization team. Own technical strategy and hands-on development for signup, onboarding, activation, checkout, billing, product discovery, notifications, analytics, and AI-powered customer experiences. Identify growth opportunities, measure business impact, establish frontend architecture and engineering standards, and collaborate with product, design, and go-to-market leaders. Mentor engineers and help build the team as it grows.

Develop and maintain accessible, responsive, high-performance web applications for government customers using React, Node.js, USWDS, and modern JavaScript. Build reusable UI components, integrate REST APIs, optimize Vite builds, support Nginx and containerized deployments, troubleshoot performance and browser issues, and collaborate with UX, product, DevOps, DataOps, and cloud teams. The role requires Agile and Git experience, U.S. citizenship, and the ability to obtain and maintain Public Trust clearance.

Build and maintain interactive website-building tools for Bask Health merchants using React, Next.js, and TypeScript. Develop reusable components, configuration panels, live previews, editing and publishing workflows, state management, validation, accessibility, automated tests, and performance improvements. Collaborate with product, design, and backend teams, integrate APIs, troubleshoot production issues, shape frontend architecture, mentor engineers, and own complex features through production.

Build and maintain responsive, high-performance web interfaces using React and JavaScript. Translate designs into reusable components, integrate REST and GraphQL APIs, optimize performance and cross-browser compatibility, and collaborate with designers, backend engineers, and product teams to deliver features.

Develop and enhance website functionality using React, optimize system performance, design technical solutions, and independently break technical specifications into subtasks. The role also involves applying SOLID principles, understanding FRP and HTTP(S)/WS(S) protocols, implementing native UX/UI components, conducting code reviews, and working with TypeScript and RxJS.

Build and deliver customer-facing web features using React and TypeScript while contributing to Node.js services, REST or GraphQL APIs, and backend-for-frontend layers. Translate customer requirements into clean, modular, well-tested code, collaborate with Product, Design, and Operations, work in an Agile environment, and mentor other engineers. Support web quality, performance, and user experience across Credible’s financial marketplace platform.

Develop scalable, engaging web applications for millions of users using React, TypeScript, and related technologies. Collaborate with product, UX, and engineering teams to design features, improve code quality, implement automated testing, optimize performance and accessibility, and support reliable distributed systems. Participate in pair programming, incident management, on-call responsibilities, and technical mentorship while evaluating new technologies and resolving blockers.

Leads frontend engineering strategy and architecture while building accessible, performant web applications. Responsibilities include developing React or Angular applications, design systems, testing and CI/CD practices, accessibility compliance, performance optimization, cloud deployment, and frontend infrastructure. The role mentors engineers, influences cross-functional technical decisions, partners with product and design teams, and delivers customer-facing solutions. It is remote with 0–10% travel and requires U.S. citizenship plus eligibility for Public Trust 6C.

Build and maintain fast, intuitive frontend applications for blockchain and Web3 products. Collaborate with product, design, and engineering teams; develop reusable components and frontend architecture; integrate wallets and smart-contract interactions; improve performance, reliability, and accessibility; participate in technical planning and code reviews; mentor other developers and establish frontend best practices.

Lead frontend-focused full-stack development for a neurotechnology platform controlling brain stimulators, managing patient data, visualizing real-time 3D data, integrating APIs, syncing cloud systems, and improving user experience. The role involves React and React Native frontend work, Python or Node.js backend development, team growth and mentorship, and collaboration on secure, scalable healthcare applications.

Senior UI Engineer responsible for building accessible, high-performance React applications and scalable front-end architecture for a pharmacy management platform. The role includes developing design-system components, defining API contracts, leading testing and code reviews, improving performance and accessibility, mentoring engineers, partnering with product and design, and using AI development tools responsibly. Candidates need strong React, TypeScript, CSS, REST API, Node.js, and PostgreSQL experience, plus end-to-end project ownership and cross-functional leadership.

Own end-to-end development of customer-facing web platform features, emphasizing React and TypeScript frontend development while contributing to Python backend services. Translate product concepts and designs into reusable, intuitive UI components, partner with Product and Design, engage directly with users, and use AI-powered tools to accelerate development while maintaining code quality and performance.

Build and maintain responsive, accessible web interfaces using React, HTML, CSS, and JavaScript/TypeScript. Integrate applications with REST APIs and back-end services, implement WebSocket features, optimize Core Web Vitals, and develop reusable design-system components. The role also involves Node.js tooling, cross-browser compatibility, code reviews, QA collaboration, and front-end testing.

Build and maintain responsive, accessible front-end interfaces using React, React Native, HTML, CSS, and Shopify. Apply UX/UI principles, collaborate with designers and multidisciplinary teams, provide clear technical feedback, and independently deliver high-quality work on complex technology or AI-related projects. Contractors complete output-based tasks and must meet weekly minimum submission requirements, with an expected start within 24–48 hours of onboarding.

Lead frontend feature releases and own user experience, performance, testing, and production health for a React and TypeScript dental practice management platform. Collaborate with backend engineers using Java Spring Boot, develop AI-powered interfaces, integrate AI tools such as Claude, participate in code reviews, improve team efficiency, and estimate development work for timely delivery.

Develop and maintain responsive Angular web applications using Angular 19+, Signals, Reactive Forms, and modular component architecture. Build complex forms, integrate REST APIs with RxJS, optimize change detection and performance, and create unit tests with Vitest or Jest. Collaborate with design, backend, and product teams, troubleshoot cross-browser issues, participate in code reviews, and follow modern front-end development practices.

Design, develop, and enhance custom SAP Fiori/UI5 applications; configure Fiori Launchpad; integrate OData services; perform UI debugging, performance optimization, code reviews, unit testing, and documentation while collaborating with backend and functional teams.

Design, build, and optimize responsive, high-performance front-end interfaces for a Web3 DEX using modern JavaScript frameworks and TypeScript. Collaborate with designers, product, and back-end teams to integrate blockchain APIs and smart contracts, mentor junior developers, troubleshoot issues, and contribute to mobile-first/PWA development while ensuring scalability and maintainability.

Build and maintain Gallatin’s Vue-based Navigator frontend, including reusable UI components, design-system primitives, offline Progressive Web App functionality, API integrations, testing, and CI/CD improvements. Ensure reliable desktop and iPad experiences, troubleshoot API and CORS issues, contribute to architectural decisions, and collaborate with product, design, and backend teams. The role also involves documentation, demos, cross-functional troubleshooting, and potentially mentoring junior engineers.

Architect and build a high-performance trading platform for active traders. Develop responsive web interfaces integrating real-time market data, low-latency execution workflows, and advanced trading tools. Collaborate with cross-functional engineering teams on large-scale initiatives, emphasizing scalability, performance, API quality, maintainability, developer experience, and end-user usability.