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

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 scalable, data-intensive products from the ground up, focusing on Java/Kotlin backend services, REST or GraphQL APIs, data access, and React/TypeScript interfaces. Responsibilities include architecture, performance optimization, testing, observability, production troubleshooting, technical documentation, and end-to-end feature ownership. Collaborate with data, reporting, design, and product teams while using AI-assisted development tools to accelerate delivery.

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.

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.

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.

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 maintain Django-based web applications, design RESTful APIs, implement frontend features (HTML/CSS/JS), optimize performance and security, collaborate with cross-functional teams throughout the development lifecycle.

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.

Build and modernize full-stack software for space mission systems, including distributed microservices, cloud-native applications, DevSecOps pipelines, automated testing, and mission operator interfaces. Integrate and test ground and flight software through simulation, emulation, and interface validation. Collaborate with space systems and operations teams, provide technical leadership, mentor engineers, and support DoD and intelligence-community programs.

Develop, integrate, test, deploy, and maintain resilient cloud-based SIGINT microservices for Intelligence Community customers. Collaborate with analysts, systems engineers, project managers, and customers in an Agile environment. Build full-stack solutions using Java, Spring Boot, Angular, TypeScript, databases, containers, cloud services, and GitLab CI/CD. Support high-availability applications, automated testing, security scanning, continuous integration, and deployment.

Own end-to-end product features for a SaaS platform serving HR, therapists, and employees. Build, scale, and evolve frontend and backend components, lead architecture and standards, collaborate with design and product, and incorporate customer feedback and QA. Work in an early-stage startup environment with product-focused ownership.

Build and ship end-to-end features for an AI neobank across frontend, backend, APIs, databases, and internal tools. Develop workflows for onboarding, payments, rewards, travel, foreign exchange, support automation, KYC, and risk. Collaborate with product, design, mobile, backend, and AI teams, while monitoring, debugging, and improving production systems.

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.

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.

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 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.