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

Develop and ship phased software projects for Affirm’s mobile card acquisition team. Collaborate with product, design, and analytics stakeholders; build web and mobile applications and scalable APIs; monitor operational metrics; support availability and on-call efforts; participate in code reviews, interviews, and team development.

Develop and launch scalable full-stack search systems using JavaScript, TypeScript, Python, or Kotlin. Collaborate with engineers and stakeholders, balance delivery speed with system reliability, debug code, participate in code reviews, write tested and extensible software, and contribute to team growth and communication.

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.

Senior full-stack engineer responsible for owning mission-critical software from requirements through deployment and sustainment. The role involves working directly with government users and technical stakeholders, architecting and building products across the stack, integrating with government IT systems, and ensuring security and compliance within DoD environments. The engineer will make product and architectural decisions, support technical proposal artifacts, and travel up to 50% to engage with mission owners in the field.

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 firmware, backend systems, and tooling for cellular IoT devices. Responsibilities include C development for STM32 microcontrollers, embedded AI integration, cellular communication, low-power optimization, device debugging and validation, and backend development with Python and Ruby on Rails. The role collaborates with hardware, electronics, and manufacturing teams and requires independently leading complex development initiatives.

Build and ship end-to-end product features across an author analytics dashboard, marketing site, free tools, billing, email, and AI-assisted functionality. Design data models and APIs, integrate third-party services, develop production LLM features, and maintain testing, monitoring, performance, and observability. The role includes code review, technical documentation, independent product decisions, and close collaboration with the founder in a remote-first environment.

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.

Own full-stack modernization of complex legacy systems for a federal client. Responsibilities include analyzing workflows, designing scalable applications, developing Java and Spring Boot backend services, building React front ends, implementing APIs and integrations, 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.

Build and operate secure, scalable full-stack identity and authentication systems using ReactJS, TypeScript, Java, and Node.js. Own features end to end, troubleshoot distributed systems, improve reliability, and lead AI-assisted development workflows using structured specifications and prompt engineering. Collaborate with product, design, security, and engineering teams while evaluating AI-generated code for quality, security, performance, and test coverage.

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.

Develop and enhance full-stack web applications for CDMRP, including portal integrations, single sign-on, microservices, responsive front-end and back-end features, REST APIs, testing, performance optimization, and legacy modernization. Collaborate with portal, systems administration, and security teams; apply UX practices; document architectures and services; and ensure compliance with DoD security procedures and STIG guidelines.

Develop and deploy responsive full-stack web applications from design through production. Translate product requirements into high-quality software, maintain pixel-perfect design standards, collaborate with product, design, and QA, and help guide technology strategy. The role acts as a technical lead on product initiatives and reports to the CTO, with a focus on AI-native development and secure fintech workflows.

Leads the design, development, and implementation of full-stack applications using C#, .NET, Angular, Azure, and SQL Server. Collaborates with cross-functional teams, ensures application security, performance, and scalability, applies Git-based version control practices, mentors developers, and stays current with emerging technologies.

Build end-to-end features in a JS/TS stack, designing scalable backend services and responsive real-time frontends. Improve observability, performance, and reliability, collaborate with product/design, and own full-stack implementation from APIs and data models to UI.

Develop and operate authentication, authorization, and identity-provider services for APIs, customer products, and internal tools. Build Go backend services, gRPC/REST APIs, shared libraries, and React/TypeScript interfaces, with occasional Java work. Own services end to end, including data modeling, deployments, monitoring, troubleshooting, integrations, testing, incident response, and on-call support.

Develops and maintains full-stack web applications, including front-end interfaces, back-end services, APIs, servers, and databases. Designs scalable solutions handling large datasets, optimizes SQL and database performance, troubleshoots complex defects, and supports architecture, testing, releases, and code reviews. Converts a complex 4D application to an ASP.NET MVC web application while integrating with existing systems. Provides technical guidance and mentorship to junior developers in a clinical and medical environment.

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.