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

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 ship customer-facing products across backend services, APIs, data models, React web interfaces, and Android point-of-sale applications. Learn unfamiliar platforms quickly, collaborate with product and design, deliver resilient code, and own testing, instrumentation, on-call support, and cleanup. The role emphasizes 0-to-1 product development, customer-focused decision-making, rapid experimentation, and using AI tools to improve development velocity and quality.

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 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.

Own the specification, design, and implementation of features for FareHarbor’s large-scale web application. Collaborate with product team members, develop scalable and performant full-stack solutions, improve automated testing, resolve technical challenges, and participate in code reviews. The role requires strong Python and JavaScript skills, experience with front-end and back-end frameworks, relational databases, performance optimization, and agile development.

Own end-to-end full-stack feature development across React/TypeScript interfaces and Elixir backend services for spacecraft modeling, simulation, and ground-control software. Drive architecture, technical debt reduction, performance, reliability, testing, API design, and production deployment. Mentor engineers, establish coding standards, collaborate with product, design, QA, operators, and astrodynamics teams, and deliver complex data-dense, real-time applications.

Contribute to full-stack features for spacecraft mission control and distributed ground control systems. Build React/TypeScript frontends and Elixir backend services, write maintainable and testable code, collaborate with operators, designers, and engineering specialists, and participate in design and code reviews. The role involves smaller, well-defined tasks under senior guidance during a three-month temporary engagement with potential conversion.

Own technical strategy and architectural decisions across multiple engineering squads. Design scalable distributed systems, APIs, data models, and cloud-native platforms while building shared systems that improve delivery. Partner with product and engineering leadership, resolve ambiguous technical challenges, establish AI-assisted development practices, and mentor engineers through design reviews and cross-team collaboration. The role requires full-stack expertise and strong influence, communication, and technical leadership in a high-stakes B2B SaaS environment.

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.

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.

Build and ship full-stack features, including REST APIs, single-page applications, data models, cloud-based containerized services, and relational database solutions. Translate product requests into deliverable work, contribute to architectural decisions, review pull requests, and protect patient data by maintaining strict PHI-handling practices. Work in a trunk-based development environment with short-lived branches, frequent releases, and continuous collaboration.

Build and own a multi-tenant web platform for managing AI infrastructure. Develop Next.js and React features, server-side authentication and API proxying, generated TypeScript SDKs, resilient data synchronization, design-system components, accessibility, performance, testing, observability, and production deployment. Collaborate with backend and globally distributed teams, review code, troubleshoot production issues, and mentor junior engineers.

Design, implement, and maintain scalable serverless backend services and responsive Next.js front-end components. Build data scrapers and integrations, improve CI/CD and IaC, mentor junior engineers, and collaborate with product and clients to solve complex compliance problems.

Senior Full Stack Engineer building scalable, high-performance web applications. Own feature design through delivery, write clean reusable code, optimize databases, work with CI/CD, containers, cloud, distributed systems, mentor teammates, and maintain zero customer-reported bugs.

Designs and develops complex full-stack software systems using Java, JavaScript, Angular, Spring Boot, AWS, and related technologies. Provides technical leadership, mentorship, code reviews, and innovation while collaborating with business partners, architects, analysts, engineers, and technical leads. Translates business logic into technical requirements, works in an Agile Scrum environment, and creates developer-facing technologies and documentation.

Build edge-focused full-stack product experiences integrating machine learning and autonomy for frontline defense users. Collaborate with designers, infrastructure teams, product teams, and ML engineers to create intuitive applications, efficient edge-deployed application stacks, and internal modeling APIs. Develop maintainable software using strong engineering practices, including design documents, code reviews, and style guides.

Designs, develops, tests, and maintains full-stack web applications, including front-end components, back-end services, APIs, servers, and databases. Builds scalable applications handling large datasets, supports architecture and database optimization, resolves complex defects, and ensures application quality and security. Participates in code reviews, planning, and releases while mentoring junior developers. The role also involves converting a complex 4D application to ASP.NET MVC 5 and integrating it with existing systems.

Build and maintain full-stack software for startup clients, including backend services, frontend experiences, new features, redesigns, bug fixes, and product improvements. Collaborate daily with product managers, designers, and engineers in a distributed, agile environment. Take ownership across the technology stack, write clean maintainable code, contribute to client missions, and support team growth and knowledge sharing.

Develop and optimize high-scale Adobe Commerce ecommerce platforms using PHP, JavaScript, Node.js, GraphQL, REST, and MySQL. Separate business logic from presentation layers, improve database and caching performance, build CI/CD validation, monitor production systems with New Relic, and create endurance load tests. Integrate identity, payment, and tax systems while mentoring junior engineers and leading offshore teams.

The Senior Fullstack Software Engineer will design, implement, and maintain features for Conveyor's SaaS platform, involving both backend and frontend work, while collaborating closely with team members and mentoring juniors.