Top Senior Front End Developer Jobs in Denver & Boulder, CO

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.

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 own accessible, performant React and TypeScript features across AgentSync’s product. Lead frontend architecture, monorepo evolution, shared component libraries, and design systems while contributing to Go or Java backend services and APIs. Translate ambiguous product problems into plans, use AI-assisted development tools, embed intelligent product experiences, and raise engineering quality through testing, code reviews, mentorship, and strong ownership.

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 or Staff Frontend Engineer responsible for developing scalable, high-performance web applications, shaping frontend architecture, mentoring engineers, and leading cross-functional feature delivery. The role requires modern JavaScript and TypeScript expertise, strong UI system design, API integration, debugging, and technical documentation skills. The engineer will also promote AI-assisted and agentic development practices, collaborate with product and backend teams, and build intuitive healthcare payment interfaces.

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.

Build and maintain customer-facing and internal web applications using React and TypeScript across Rails-embedded and standalone environments. Own shared component libraries, implement Figma designs, improve frontend performance, integrate REST APIs, expand automated testing, and investigate production issues. Collaborate closely with design, product, and backend engineering while documenting maintainable patterns and applying coding agents effectively.

Designs, develops, tests, deploys, operates, and maintains scalable full-stack software products. Builds React-based enterprise applications, writes production-ready code, performs code reviews, improves reliability and performance, integrates APIs, and follows security, compliance, accessibility, and DevOps practices. Collaborates across teams using agile methods, analyzes failures, prioritizes work, and contributes to technology transformation and continuous improvement.

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.

Develop and maintain performant frontend web applications for real-time, mission-critical data. Responsibilities include UI architecture, API integration, responsive design, automated testing, performance optimization, security remediation, code reviews, Agile collaboration, documentation, and frontend reliability improvements.

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.

Owns the design, development, security, performance, and scalability of Cerby’s cross-browser Manifest V3 extension. Builds React and TypeScript experiences across extension surfaces, manages service-worker synchronization and authentication workflows, and ensures secure credential handling. Responsibilities include dependency and supply-chain security, testing, observability, code reviews, mentoring, cross-functional collaboration, and production delivery in an agile remote environment. The role also promotes responsible AI-assisted 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.

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.

Lead the evolution of Seeq’s frontend infrastructure, including React systems, component libraries, state management, styling architecture, and reusable application patterns. Drive large-scale refactors, improve developer experience, ensure accessibility and performance, evaluate open-source tools, and establish technical standards adopted across teams. Collaborate with designers, product teams, and engineers through architecture reviews, documentation, code reviews, mentoring, and cross-team delivery.

Own the frontend architecture and implementation of a greenfield legal technology product using React and TypeScript. Build complex, secure, role-aware workflows; establish component, state-management, routing, form, validation, accessibility, performance, and testing standards; integrate backend APIs and AI-enabled capabilities; and provide technical guidance to frontend developers.