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

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.

Lead software engineering teams developing, integrating, deploying, and maintaining full-stack mission applications for DoD and intelligence customers. Build prototypes and high-performance user interfaces, integrate APIs and independent capabilities, collaborate with military and government operators, and conduct deployment, field testing, and troubleshooting in secure operational environments. Manage customer relationships while ensuring software quality, reliability, and performance.

Develop and deploy customer-focused web, mobile, and backend applications across the full software stack. Design major features, contribute to architecture decisions, conduct code reviews, and ensure secure, high-quality implementations. Collaborate with stakeholders and cross-functional teams using Agile and SDLC practices. Manage version control, CI/CD, environments, and releases; maintain automated test coverage and perform root-cause analysis. Build and optimize relational data solutions using SQL Server, including complex queries, stored procedures, and performance tuning.

Build and maintain scalable e-commerce and marketplace features across Node.js, React, MySQL, and MongoDB. Own complex features end to end, design backend services and APIs, integrate PunchOut procurement systems, improve platform security and reliability, conduct code reviews, and mentor engineers. The role requires strong full-stack JavaScript and TypeScript expertise, e-commerce domain experience, and the ability to work autonomously on high-volume transactional software.

Build and own CRM features and workflow automations supporting sales, marketing, onboarding, and support. Develop full-stack functionality using Next.js, FastAPI, Inngest, and related technologies; partner with teams to automate workflows; create agentic solutions for enrichment and task automation; and manage features from planning through monitoring and refinement. The role requires strong web development expertise, product sense, autonomy, communication, and experience with modern JavaScript or TypeScript frameworks and orchestration tools.

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.

Leads technical vision and strategy for Affirm’s Marketplace, Search, Ads Platform, and consumer experiences. Designs scalable full-stack platforms, guides architecture and technical excellence, coordinates initiatives across engineering teams, mentors engineers, and drives reliable delivery of customer-focused products across iOS, Android, and Web.

Design, develop, test, deploy, and support scalable full-stack cloud-native applications using Java, Spring Boot, Vue.js, Python, and FastAPI. Build secure APIs and operate AWS applications with Docker, Kubernetes, and Infrastructure as Code. Collaborate with product, systems, and architecture teams to deliver features end to end. Apply AI-assisted development throughout coding, testing, debugging, code review, and documentation while validating quality, security, and maintainability.

Leads technical direction and develops fullstack purchase experiences using Ruby on Rails and Vue.js. Designs resilient transactional flows, integrates billing and CRM systems, improves reliability and rollout safety, mentors engineers, reviews code, reduces technical debt, and participates in incident response. Partners with Product, Design, Billing, and Support to improve GitLab’s purchase, subscription, discount, and upgrade workflows.

Provides technical leadership for AI Trust and Governance engineering, designing scalable cloud-native services and distributed systems. Responsibilities include architecture, systems programming, concurrency, testing, debugging, deployment, release management, cross-team collaboration, and mentoring engineers. The role requires strong Java or C skills, expertise in distributed systems and consensus algorithms, and ownership of enterprise platform features from design through delivery.

Build and operate scalable, accessible, high-performance web experiences for Calendly’s marketing website and Help Center. Own projects from technical design through deployment and iteration, develop frontend architecture and CMS integrations, improve SEO, AEO, accessibility, Core Web Vitals, and reliability, and collaborate with Marketing, Content, SEO, Design, Product, and Engineering. Provide technical leadership through testing, code reviews, documentation, mentorship, and architectural improvements.

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.

Own and evolve scalable distributed systems, REST APIs, backend services, and core product areas. Design solutions, improve resilience, reduce technical debt, and drive modularization. Use AI-first and agentic development practices, evaluate emerging AI tools, and help integrate AI across engineering workflows. Collaborate asynchronously with product, data, and go-to-market teams while improving engineering tools, processes, and system reliability.

Build end-to-end user features under senior guidance: implement REST endpoints in Node.js/TypeScript, microservices in Python, maintain PostgreSQL schemas, process background jobs with QStash/Upstash, deploy to Cloudflare Workers/Pages/R2, write tests, and collaborate with product/design on React UI components.

Build and maintain end-to-end features across backend (Node.js/TypeScript, Python) and frontend (React/TypeScript). Model Postgres schemas, integrate queues (QStash/Upstash), deploy on Cloudflare edge, write tests, enforce CI/CD, and harden systems for security and performance in regulated environments.

Build and maintain core products and collaborate on larger consulting projects using TypeScript, Python, FastAPI, Next.js, GCP, and generative AI frameworks. The role involves hands-on software development within a rapidly growing, remote team serving Saudi Arabia and the GCC.

Design and implement backend features in Go, build data pipelines and REST APIs, work with PostgreSQL and AWS, contribute to scalable system design, and optionally develop React.js user-facing features while collaborating in a fast-paced AI-focused startup.

Design, build, and maintain production-grade .NET web applications and APIs on Azure. Own full-stack delivery from data models and SQL to front-end components, CI/CD, testing, and architecture. Collaborate with product and delivery teams, participate in code reviews, and ensure secure, observable, well-tested services.

Design, build, and optimize scalable cloud and web software with focus on infrastructure, performance, and hardware integration for IoT devices. Collaborate with hardware teams to ensure connectivity and high availability, implement new features, and improve system efficiency.

Join as an early founding full-stack engineer to architect, build, and deploy a scalable platform serving AI-driven voice applications. You will own frontend and backend development, design infrastructure with the CTO, and deliver reliable production systems for enterprise customers.

Lead architecture and implementation of scalable web applications using NestJS and Next.js. Build and optimize PostgreSQL schemas and queries, implement responsive UIs with Tailwind CSS, integrate LangChain-driven AI features, manage authentication with Clerk, and create end-to-end tests and automation with Puppeteer to ensure launch readiness and reliable user experiences.

Implement and maintain full-stack features for a career-intelligence platform: architect NestJS/Next.js applications, manage PostgreSQL schemas and queries, build responsive UIs with Tailwind, integrate LangChain-powered AI, implement authentication with Clerk, and create end-to-end tests and automation with Puppeteer to ensure launch readiness and performance.

Join as the founding full-stack engineer to extend a TypeScript React/Next.js prototype, design product features, integrate AI/OCR, write tests and infrastructure, talk to users, and iterate quickly to drive growth.

Design, build, and maintain cross-platform mobile applications and end-to-end web features. Implement front-end interfaces, back-end services and RESTful APIs, optimize databases, write tests and documentation, perform code reviews, and collaborate with UX, QA, and DevOps to deliver high-quality, secure, and performant solutions.

Work on front-end and back-end web projects: create and redesign websites, build sitemaps and wireframes, collaborate with teams, and focus on UI/UX and performant back-end functionality.