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

The Senior Full-Stack Engineer will manage client relationships, design integration solutions, and ensure seamless delivery and optimization of technical workflows, while leveraging AI for efficiency.

Build and launch scalable fullstack web applications and APIs for Affirm’s Ads Platform. Collaborate with product, design, analytics, and engineering partners to break projects into deliverable phases, make technical trade-offs, write tested and extensible code, monitor service metrics, support on-call operations, review code, and participate in team development and interviews.

Build and ship full-stack web and mobile experiences across Affirm’s consumer products. Break down projects, collaborate with product, design, and analytics teams, develop scalable APIs, write well-tested code, monitor service health, participate in on-call support, review code, and contribute to engineering growth and interviewing.

Lead design and delivery of full-stack basketball scoring, statistics, and postgame features. Build scalable backend services and APIs with TypeScript and Node.js, develop React web experiences, support iOS and Android products, and make architectural decisions. Collaborate across product, design, and engineering teams, ensure code quality and system reliability, mentor peers, and contribute to technical standards and tools.

Lead the architecture and delivery of GitLab’s data products, including near-real-time data ingestion, knowledge graph integrations, data marketplaces, observability, and data-sharing APIs. Translate ambiguous 0-to-1 initiatives into roadmaps, resolve cross-team dependencies, ensure operational readiness across deployment surfaces, and mentor engineers. The role requires deep full-stack expertise, technical leadership, and experience with AI-powered orchestration and multi-tenant SaaS systems.

Develop and support software, automation tools, dashboards, and alarms for cloud infrastructure, cost attribution, and cloud efficiency. Collaborate with cross-functional teams and senior engineers to design reliable systems, APIs, databases, tests, and AI agents. Contribute to architecture and automation strategies while maintaining strong security, communication, and delivery practices.

Build backend-focused Java/Kotlin APIs and data-driven product features, while contributing to React dashboards and workflows. Design scalable systems, participate in architecture and code reviews, troubleshoot production issues using observability tools, and collaborate with data, reporting, design, and product teams to launch emerging products.

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.

Build and review full-stack software environments for AI training. Develop frontend and backend features, integrate APIs, debug issues across UI and data layers, improve code quality, document technical reasoning, and review peer submissions. The role requires frontend and backend development experience with frameworks such as React or Angular and stacks including Node.js, Python, Java, or Go. Prior AI experience is not required.

Design, build, and deploy secure, high-performance, scalable cloud-native applications supporting Ariba P2P. Work full-stack in Java using Spring Boot and the SAP BTP Cloud Foundry CAP (Java) model, applying resiliency, security, and performance best practices.

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 scale a fintech platform across accounting, tax, and banking. Own feature lifecycle from design to deployment, write backend and frontend code, improve infrastructure and reliability, and collaborate with product and design to deliver customer-focused features.

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 maintain scalable React/Node/TypeScript web applications, design RESTful APIs and microservices, optimize performance, troubleshoot full-stack issues, collaborate on features, adopt AI-assisted tools, and support CI/CD and cloud integrations.

Lead the architecture and technical direction of Alpaca’s Trading API customer experience. Own identity, authentication, authorization, account models, partner access, and customer-facing trading applications. Drive backend modernization, real-time trading features, security practices, safe production delivery, observability, incident prevention, design reviews, and engineering mentorship. Collaborate with Product, Design, Compliance, Security, Brokerage Operations, and platform teams while remaining a hands-on principal contributor.

The Senior Full Stack Engineer will modernize legacy systems to microservices, maintain .NET applications, optimize SQL databases, and develop frontend interfaces.

Maintain and modernize a stable .NET/SQL Server platform while leading migration from monoliths to cloud-native microservices. Design APIs and event-driven patterns, containerize deployments, optimize backend .NET apps and SQL performance, and build responsive frontends integrated with microservices. Collaborate across cross-functional teams to ensure scalable, highly available systems.

Build responsive web applications and scalable frontend/backend services, design secure APIs and databases, implement AI-powered search and asset management features, collaborate on system architecture, and optimize performance and UX for a cloud-native DAM platform.

Own end-to-end full‑stack features: design data models and clinical APIs, build backend services (TypeScript/Nest.js/Node.js on AWS), and implement React+TypeScript frontends. Deliver responsive clinical workflows, reimbursement integrations (MDS), FHIR extensions, EHR/vendor integrations, CI/CD, monitoring, and HIPAA/SOC2 readiness. Partner with clinicians, visit facilities, mentor hires, and iterate with product and design.

Own full-stack modernization of complex federal legacy systems using Java, Spring Boot, REST APIs, React, and relational databases. Responsibilities include analyzing workflows, designing scalable applications, building integrations, developing user-facing components, supporting the full SDLC, troubleshooting across application layers, and collaborating with technical and non-technical stakeholders. The role is fully remote and requires U.S. citizenship with the ability to obtain and maintain Public Trust clearance.

Design, develop, test, deploy, and support enterprise full-stack applications using React, Java/Spring Boot, and Python. Build secure APIs, microservices, integrations, chatbot interfaces, and cloud-native solutions. Work with Azure or AWS, Docker, Kubernetes, CI/CD pipelines, databases, messaging systems, and enterprise security practices. Collaborate in agile teams, participate in architecture discussions, refine requirements, conduct code reviews, and maintain quality through automated testing. Experience integrating AI or generative AI solutions is preferred.

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.

Build and scale backend-focused systems supporting truckload freight operations, including high-volume carrier quotes, automated transactions, distributed services, and APIs. Design scalable data models and architectures, contribute across the React and TypeScript stack, make key technical decisions, mentor engineers, and collaborate with product leadership. The role also involves developing AI-powered logistics tools and maintaining reliable, secure infrastructure on Kubernetes and GCP.

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.