Top Full-Stack Engineer Jobs in Denver & Boulder, CO

The Full Stack Engineer will develop features for a dynamic web application, collaborate with team members, enhance performance, and improve automated tests.

As a Fullstack Engineer, you'll design, build, and operate web applications, collaborating with product teams and mentoring peers while ensuring best practices in coding and system architecture.

Build and maintain FareHarbor.me, a managed WordPress site platform. Develop PHP and JavaScript features, craft themes/plugins and Gutenberg blocks, collaborate with design and product, review PRs, write docs, and improve accessibility, performance, and editor UX across thousands of client websites.

Build and own end-to-end full-stack features across backend services and user-facing applications. Contribute to system design, reliability, performance, observability, and engineering practices while collaborating with product and design.

Modernize a large fintech platform by building NestJS services and Next.js UIs, migrate transactional data to relational schemas, write comprehensive tests, identify and fix legacy problems, design scalable solutions that coexist with legacy systems, and use AI tooling responsibly to increase engineering velocity.

Seeking a full stack engineer to develop applications, requiring skills in Node.js, SQL, and modern JavaScript frameworks with a focus on scalability and performance.

Design and build a high-performance, AI-native web trading experience for sophisticated retail traders. Ship core trading workflows (order entry, positions, blotter, watchlists, alerts), implement trustworthy AI UI patterns, collaborate with backend engineers on low-latency contracts, and iterate quickly with users and stakeholders to deliver end-to-end product features.

Develop fullstack web applications, enhance platform performance, collaborate on high-impact opportunities, and ensure stable, scalable solutions. Engage in rapid iterations and be a committed team player.

Develop and implement full stack features for a healthcare platform, focusing on both frontend (React) and backend (Node.js) development. Responsible for performance optimization, API creation, testing, and collaboration with data engineering teams.

Lead and deliver software solutions, oversee full-stack architecture, mentor engineers, and drive cross-functional initiatives for spacecraft modeling and control platforms.

Join a small team to improve a tech product aimed at upskilling users in MENA, working with JavaScript and Node.js in a collaborative remote environment.

Build and maintain the full-stack platform connecting Blissway hardware to drivers, partners, and agencies. Own public user surfaces, partner integrations (DMVs, mailhouses, fleet vendors, ACH), platform/deployment tooling, service infrastructure, and internal access management. Ensure secure, robust, production-ready systems and tooling that support a fast-moving, small engineering team.

Design, build, and maintain scalable backend services and APIs for commerce workflows using Python/Django. Improve reliability, performance, and observability, operate AWS deployments, work with PostgreSQL and event-driven architectures (SNS/SQS), modernize legacy systems, and support CI/CD, testing, and production troubleshooting.

Lead full‑stack design and delivery of customer-facing web experiences (Browse, Navigate, Preview). Own architecture, APIs, data models, rollouts, observability, on‑call readiness, and cross-team alignment, using approved AI-assisted workflows while ensuring technical quality and reliability.

Volunteer Principal Full Stack Engineer to lead and contribute across frontend and backend (React/React Native, Node.js, MongoDB). Own feature development, mentor engineers, collaborate with product/design, ship scalable code, and support CI processes. Must commit 4+ hours weekly and attend a weekly standup; first task includes launching a fundraising campaign.

Build and ship full-stack features for customer-facing Console and Playground, plus internal tools. Design and maintain APIs and backend services, implement accessible performant frontends, translate product requirements into incremental work, and improve code quality through reviews and design discussions.

Lead technical direction and delivery for the Acquisition & Onboarding full‑stack team. Build and maintain mobile (React Native/native) and web experiences, backend services at scale, and operational tooling. Drive architecture, mentor engineers, ensure reliability/monitoring/on‑call readiness, collaborate with product and design, and improve dev processes, testing, and release practices to impact conversion and retention.

Build, customize, and maintain WordPress and Shopify websites; manage CRM setup and integrations (HubSpot, HighLevel); handle full-cycle website and CRM builds; optimize performance, SEO readiness, and conversions; troubleshoot issues; collaborate with stakeholders and communicate progress, blockers, and timelines.

Lead and mentor a web development team building features and site improvements in a LEMP stack. Develop front-end interfaces (HTML/CSS/JavaScript), perform database development and SQL optimization, integrate systems via JSON/XML/PHP web services, and apply website optimization, secure coding, and SEO best practices.

As a Fullstack Engineer, you will develop and enhance user experiences for members and providers at Thyme Care, collaborating with teams to deliver scalable products.

The role involves building and integrating full-stack features for an AI chat application, focusing on reliable workflows and real-time AI interactions.

As a Full Stack Engineer, you will design, develop, and maintain scalable solutions for data-driven products, collaborating with cross-functional teams.

Design, build, and maintain full-stack web applications using modern JavaScript/TypeScript, Node.js and React. Develop RESTful APIs, scalable back-end services, reusable front-end components, and ETL/microservice integrations. Collaborate with product, UX, QA in Agile teams, write unit tests, optimize performance, and document code and APIs.

Develop and deliver production-ready web experiences for marketing using React, Gatsby, and Tailwind. Build API integrations, maintain a lightweight codebase and design-system components, ensure accessibility, performance, SEO, and multi-region support, participate in code reviews, and help shape tooling and best practices across the team.

Design, implement, and optimize full-stack solutions. Collaborate with cross-functional teams, participate in code reviews, analyze and improve system performance, and stay current with industry technologies.