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

Develop and ship full-stack web and mobile experiences across Affirm’s consumer app and website. Collaborate with product, design, analytics, and engineering teams to break down projects, make technical decisions, write tested and extensible code, launch scalable APIs, monitor service health, support on-call operations, review code, and participate in team development and interviewing.

As a Fullstack Engineer, you'll design, build, and operate web applications, collaborating with product teams and mentoring peers while ensuring best practices in coding and system architecture.

Lead full-stack mission engineer who designs, develops, integrates, and deploys software for DoD/IC missions. Lead cross-functional teams to build high-performance frontends and cohesive systems, collaborate with military customers for product discovery, and deploy and field-test solutions in secure operational environments (travel ~1 week/month).

Design and implement full‑stack, low‑latency web-based Ground Control Station and C2 systems (map-centric UIs, real-time telemetry, video streaming), lead architecture and APIs, mentor engineers, support field tests and mission deployments, and ensure interoperability with C2 standards.

Build full-stack web applications and containerized microservices for defense and intelligence customers. Develop front-end and back-end services using APIs or message buses, employ observability tools, follow Agile and CI/CD practices, and collaborate on distributed teams. Must hold active TS/SCI clearance and work on-site.

Design, develop, and maintain full‑stack web applications and containerized microservices for defense and intelligence customers. Build front-end and back-end services, integrate APIs/message buses, use CI/CD, monitoring, and collaborate on distributed Agile teams to deliver mission-focused software.

Build and scale consumer-facing mobile and web applications and backend services. Own features end-to-end across frontend and backend, optimize databases and queries, integrate third-party APIs, implement algorithms for risk and transaction evaluation, improve reliability and CI/CD, and contribute to testing, monitoring, and internal tools to support customer operations.

Design, develop, and maintain full-stack web and backend microservices for defense/intelligence customers. Build containerized services, front-end applications, and API/message-bus integrations using observability tools and CI/CD in an Agile, distributed team environment.

Senior fullstack engineer to build and scale Brigit's consumer finance platform. Own end-to-end features across frontend (React/React Native/TypeScript) and backend (Java/REST/SQL), optimize database and APIs for high scale, integrate 3rd-party services, implement risk and transaction algorithms, improve CI/CD, testing, monitoring, and internal tooling to support millions of users.

Design, develop, and maintain full-stack web applications and containerized microservices for defense/intelligence customers. Build frontend and backend services, integrate APIs or message buses, use CI/CD, and collaborate on Agile teams while operating in an on-site cleared environment.

Build full-stack web applications and containerized microservices for defense/intelligence users. Develop front-end (React/Vue) and back-end services (APIs/message bus), use CI/CD, observability tools, and collaborate in Agile teams on mission-focused signal and image processing software.

Design, build, and maintain front-end and back-end components for containerized microservices supporting defense and intelligence users. Work on APIs or message-bus integrations, implement software engineering best practices, participate in CI/CD and Agile processes, and collaborate with distributed teams.

Design, implement, and maintain front-end and back-end components for containerized microservices. Work on signal/image-processing software for defense/intelligence customers, participate in Agile CI/CD teams, and collaborate across distributed teams.

Develop, maintain and evolve a high-scale US sports trading platform. Build React/TypeScript frontends, backend microservices, optimize SQL and performance, implement CI/CD and automated testing, mentor junior engineers, and collaborate with stakeholders and architecture teams to ensure resilience and integration.

Build and maintain the TypeScript-based Duo Client SDK, including Node.js core packages, public APIs, browser-compatible modules, Vue 3 client components, and platform adapters. Responsibilities include migrating consumers from the GitLab Language Server, managing versioning and deprecation paths, strengthening credential security, optimizing browser performance, writing tests, conducting code reviews, and participating in on-call support.

Build and maintain full-stack software across data models, APIs, user interfaces, workflows, and production systems. Develop accessible, form-driven applications using TypeScript, Node.js, NestJS, React, and Next.js. Design transactional and flexible databases, implement asynchronous processing, and write unit, integration, and end-to-end tests. Participate in code reviews and technical design discussions while improving scalability, security, reliability, and WCAG compliance. Own features end to end with growing autonomy and collaborate with senior engineers and technical leadership.

Build and operate customer-facing applications and shared platform services using TypeScript, Node.js, React, and Next.js. Own API contracts, SDKs, data models, cloud delivery, observability, testing, and service adoption across engineering teams. Lead AI-assisted development practices, delivery automation, reliability improvements, technical documentation, design reviews, and mentorship. The role also involves evolving financial, authentication, workflow, and event-driven systems in a hands-on individual contributor capacity.

As a Senior Software Engineer, you will design and build a cutting-edge identity search platform and implement AI systems for defense applications, working closely with cross-functional teams to enhance user workflows and support national security.

Build and own complex frontend features using Vue 3 and TypeScript while developing the Python services and APIs that power them. Improve performance, accessibility, testing, CI/CD, and observability; collaborate with product and design; mentor engineers and apply AI-assisted development tools responsibly to accelerate productivity and maintain quality and security.

Design and implement scalable backend services for payment and transaction workflows using Java. Own end-to-end features from data model and APIs to Angular frontends, improve reliability and performance, refactor legacy systems, troubleshoot production issues, and collaborate with product and design. Leverage AI-assisted development tools responsibly and share best practices across the team.

As a Fullstack Software Engineer, you'll design, develop, and maintain scalable frontend and backend systems while collaborating across teams.

Leads technical roadmap and architecture while building scalable full-stack SaaS features hands-on. Owns the full development lifecycle, establishes engineering, testing, security, and AI-assisted development standards, and guides cloud-native system evolution. Collaborates across product and engineering, mentors engineers, mitigates technical risks, and drives quality, performance, observability, and continuous improvement.

Lead architecture, modernization, and development of Group Insurance applications. Modernize mainframe monoliths into Java microservices and micro-frontends on cloud, mentor distributed Agile teams, collaborate with enterprise architecture, product owners and infrastructure, and enable test automation and integrations. Approximately 10% domestic travel.

Responsible for leading a team of engineers, supporting product development, identifying technical issues, and ensuring high-quality code delivery in backend systems at scale.

Design, build, and maintain automation tools and systems to deploy and manage cloud-based infrastructure. Collaborate with cross-functional teams to analyze requirements, implement APIs and database schemas, write automated tests, and contribute to architectural and automation strategies while emphasizing security and production stability.