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

Own and evolve the front-end architecture for a high-throughput, real-time trading app using Next.js, React, and TypeScript. Build pixel-accurate, accessible, responsive UIs under strict performance budgets; optimize rendering, state management, data flow, and bundle size for sub-second interactions. Integrate with REST and WebSocket APIs, lead end-to-end feature development, set engineering standards, mentor engineers, and contribute across the stack when needed.

As a Senior Software Engineer, lead design and development of core backend services while mentoring other engineers and enforcing best practices.

Design, implement, and maintain frontend applications and internal tools. Own delivery of high-visibility features, collaborate with cross-functional teams, mentor peers, and ensure performant, accessible, polished user interfaces integrated with backend systems.

The Senior Frontend Engineer will build and enhance core product experiences using Angular 2+ and React, ensuring high-quality code and collaboration with other teams.

Early-stage frontend-focused product engineer to own web and mobile experiences (React, React Native, Expo). Design conversational AI-native interfaces for financial planning, build in TypeScript across stack, define frontend architecture and component system, use agentic engineering tools, contribute to multi-model AI orchestration, and iterate quickly with founders and users.

Own and evolve Roo's frontend platform and design system, building tooling, AI-assisted workflows, and shared UI architecture to accelerate web and mobile product development. Lead migrations, framework upgrades, developer experience improvements, and integrations with design and prototyping tools.

The Senior Full Stack JavaScript Developer will build and maintain user interfaces using React and Next.js, integrate with Node.js backends, and guide other developers. Responsibilities include ensuring accessibility, performance, and reliability of features, engaging in code reviews, and collaborating closely with product teams.

As a Senior Frontend Engineer, you will design and build web applications, owning major UI projects, collaborating with cross-functional teams, and optimizing performance for a seamless user experience.

Design and implement scalable frontend solutions using JavaScript/TypeScript and React. Drive architecture discussions, ship features with minimal guidance, maintain code quality and styling standards, collaborate across agile teams, ensure performance and scalability, and manage end-to-end feature lifecycles in a fast-moving environment.

Lead design, development, and maintenance of enterprise-grade React + TypeScript applications. Own front-end performance, responsiveness, and security; integrate with .NET/Azure backends; mentor junior developers; perform code reviews and debugging; modernize legacy apps; collaborate with designers, offshore teams, and stakeholders in Agile ceremonies.

Build and evolve the guest-facing booking experience using React and TypeScript. Collaborate with product, design, and backend to ship performant, accessible, and well-tested features. Improve conversion through profiling and experimentation, lead technical discussions and frontend architecture, mentor teammates, and champion engineering best practices across testing, performance, and accessibility.

Design, build, and maintain scalable Angular frontend applications using TypeScript, RxJS, and Tailwind. Implement complex UI features, mapping/geolocation with Google Maps API, state management, testing (Jasmine/Karma), error monitoring (Sentry), and CI/CD workflows while collaborating cross-functionally and supporting multiple environments.

Lead frontend and mobile rebuild of a healthcare scheduling platform using Vite + React 19 and Expo/React Native with a shared TypeScript layer. Own identity and access migration to a modern IAM, implement push notifications, build a component library/design system, instrument analytics and session replay, enforce WCAG 2.1 AA accessibility and performance standards, mentor mid-level engineers, and contribute to hiring.

Build the realtime, HIPAA-compliant messaging and collaboration frontend ('Pulse') that makes an AI colleague feel human. Implement complex interactive data visualizations, micro-interactions, and high-performance accessible interfaces. Work embedded with product and design, own UI quality, iterate on AI-driven specs, and deliver production frontend experiences clinicians will trust.

Lead frontend product experiences across web and mobile using React/React Native and TypeScript. Design conversational, AI-native financial planning interfaces, define frontend architecture and component systems, and contribute to AI layer, multi-model orchestration, reliability, and observability. Work cross-functionally across backend, infra, analytics, and product in a seed-stage, remote environment to ship fast, user-trusted experiences.

Develop and improve real-time drone tele-operations features, cloud-based products, and quickly prototype new front-end experiences while transitioning to a new tech stack.

Expand and maintain Hudl's front-end platform to accelerate product teams: design and implement scalable, performant, accessible front-ends and tooling (Vite, Next.js), consult and review front-end work, support adoption of design systems, and mentor teams to improve developer experience.

Build full-stack vertical slices for a mission-critical government system with a frontend focus: React/TypeScript UIs, Node services, Prisma schemas, PostgreSQL, and AWS. Use agentic AI tools, lead design-system/accessibility, apply TDD and Playwright E2E testing, maintain CI/CD, and iterate continuously with stakeholder review.

Develop AI/ML-powered features in ClickHouse Cloud, focusing on frontend and API architecture, UI/UX, and integrations with AI systems.

Build and scale high-performance, data-driven React web applications and visualization-heavy, map-based interfaces. Integrate with REST/GraphQL APIs, optimize rendering for real-time large datasets, contribute to frontend architecture, reusable UI systems, testing, and cross-functional collaboration to support mission-critical workflows.

Lead architecture and implementation of Aragorn AI's frontend: build scalable React/TypeScript applications, evolve micro-frontend architecture, develop and maintain a reusable design system, optimize performance, collaborate with design and backend teams, own CI/CD for frontend, and drive frontend technical standards and documentation.

The role involves developing large-scale applications using HTML, CSS, JavaScript, and React/WordPress, code reviews, and crafting UI components while ensuring high quality and accessibility.

Lead the development of a scalable frontend web application for an AI photo platform, recommend technologies, and ensure performance optimization.

The role involves building creative tools for content editing, enhancing features with PixiJS and WebGL, and improving collaboration workflows.

Own and evolve the customer-facing React app and frontend architecture. Build accessible, performant, mobile-responsive features, a shared component library/design system, and AI-assisted experiences. Partner with Product, mentor engineers, write well-tested code, review PRs, and occasionally work with backend Java/Go and AWS.