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

The Senior Fullstack Engineer will build and manage enterprise authentication systems, improve user session management, ensure security compliance, and support internal API usage across services, while enhancing performance and reliability.

The Senior Full Stack Engineer will develop and maintain features for Engrain's products, integrate AI tools, mentor junior staff, and support DevOps practices.

Design, build, deploy, and optimize scalable full-stack applications integrating databases, APIs, and AI/LLM workflows. Lead architecture, CI/CD (ArgoCD, GitLab), Airflow pipelines, and collaborate cross-functionally to deliver production-grade fintech solutions.

Lead and modernize core Laravel/PHP backend systems and high-performance React/TypeScript frontends. Architect integrations (MLS/RETS/RESO), improve video processing and media delivery, strengthen CI/CD and Docker deployments on AWS/Rackspace, introduce AI-driven automation, and provide senior technical leadership and mentorship.

As a Senior Fullstack Engineer, you'll contribute to backend development for Toast's New Ventures team, collaborating on architecture and launching MVPs while addressing unmet operator needs.

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.

The Senior Full-Stack Developer will design, build, and maintain AIO Logic's cloud-based AXIS platform, utilizing React and Java/Spring Boot to deliver software solutions for complex financial workflows, collaborating with cross-functional teams, and mentoring junior developers.

The Senior Full Stack Engineer develops and maintains the US Sports platform, coaches junior engineers, collaborates with stakeholders, and ensures high system performance under demand.

The Senior Full Stack Engineer will design and implement APIs with NodeJS, develop UIs with React, manage data pipelines, and deploy projects on AWS.

The Senior Full Stack Developer will build end-to-end solutions, collaborate in a remote environment, and write technical documentation. The role requires expertise in Ruby on Rails and various programming paradigms.

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.

Design and build agent-powered mission consoles, collaborate with stakeholders to improve user workflows, and maintain agentic workflows for mission outcomes.

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.

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

This role involves designing and developing scalable web applications, leading projects, mentoring engineers, and ensuring quality through best practices and collaboration.

As a Senior Full Stack Engineer, you'll design and build cloud-native applications for the payments platform, ensuring reliability and scalability. Collaborate with engineering teams to deliver solutions and maintain production systems.

Build and own data-driven dashboards and backend services for DeFi risk analysis. Develop React frontends, GraphQL APIs, and cloud-native data pipelines. Collaborate with research and protocol teams, mentor junior engineers, drive architectural improvements to the Alert Portal, ensure code quality through testing and reviews, and identify product and technical enhancements.

Ship full‑stack SaaS features and fixes, leverage AI‑agentic development workflows to boost throughput, build internal agent/codegen/test pipelines, validate AI output with tests and reviews, decompose monoliths, and collaborate with product and customers on deployments and incidents.

Build end-to-end features, design intuitive interfaces, manage asynchronous backend jobs, and contribute to open-source efforts, while leading project development from concept to monitoring.

As a Senior Full Stack Developer at Capnexus, you'll design and build a cloud-native subcontractor pre-qualification platform using AWS, incorporating AI and modern frontend/backend technologies, ensuring seamless integration and deployment.

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

The Senior Full Stack Engineer will maintain legacy .NET systems while leading modernization efforts towards a cloud-native microservices architecture, managing both backend and frontend development tasks.

The Senior Full Stack Engineer will design and build APIs, develop user-facing features, mentor other engineers, and ensure high-quality software delivery.

As a Senior Full-Stack Engineer, you will build features across React/TypeScript and Python/Django, shape product outcomes, and collaborate with cross-functional teams to ensure user satisfaction and engineering quality.

Design, build, and maintain scalable web applications using Python and React. Collaborate with teams and ensure application security and performance.