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

Design, build, and maintain scalable full‑stack web applications using Python (FastAPI/Django/Flask) and Node.js frameworks (Next.js, Nest.js). Build React front ends, architect RESTful APIs, work with SQL/NoSQL databases, implement testing and security best practices, leverage AWS cloud services and AI-assisted development tools, collaborate with product and design, perform code reviews, and mentor junior engineers.

Design, build, and scale backend services and APIs for high-volume financial transactions and rewards. Own feature delivery across payments, rewards, account services, and partner integrations, improve reliability and observability, and collaborate with frontend and mobile engineers.

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.

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 Developer will develop web applications, facilitate Scrum ceremonies, guide agile practices, and drive project goals.

Lead the development of Coperniq's platform by designing, developing, and maintaining scalable full-stack solutions while collaborating with teams and mentoring juniors.

The Senior Software Engineer will design, develop, and optimize scalable PHP APIs and web applications, collaborating with product and design teams to support product development and implement best coding practices.

The Full Stack Engineer will architect and build 'The SOURCE®' platform, integrating AI and automating workflows while ensuring scalability and simplicity.

The Senior Full Stack Engineer will design and maintain features across backend and frontend systems, focusing on scalability and security while collaborating on production-grade solutions in a fast-paced environment.

As a Senior Full Stack Engineer, you'll build interactive customer experiences, manage backend architecture, write well-tested code, and ensure smooth production processes.

Design, build, and maintain backend and full-stack features primarily in Ruby on Rails with Hotwire. Own and improve CI/CD pipelines, collaborate with product and business teams to automate solar development, valuation, and loan servicing workflows, and drive architectural and technical direction to support rapid company growth.

Lead design and delivery of provider-facing backend services and frontend applications. Own features end-to-end, mentor engineers, build React/TypeScript interfaces, design DRF REST APIs and database schemas, use LLM tooling (Claude) to accelerate development, and operate services on Kubernetes/GCP with Datadog for monitoring.

The Senior Full-Stack Developer will manage architecture and delivery for a web application, integrating historical data into SAP S/4HANA. Responsibilities include overseeing development, integrating cloud identity, and leading architectural documentation.

Develop consumer-centric web applications, enhance usability, collaborate with designers, implement backend software and APIs, write tested code, and follow agile development cycles.

As a Senior Full-Stack Engineer, lead design and development of complex search features, optimize development processes with AI tools, and mentor juniors in a collaborative environment.

The Senior Full-Stack Engineer will design, implement, and maintain systems for Trading API customers, focusing on both frontend and backend development, while leading projects and mentoring peers.

The Senior Full Stack Engineer will design, build, and scale healthcare integrations, ensuring high security and quality, while collaborating with cross-functional teams and supporting enterprise-level integrations.

Build and ship complex consumer-facing full stack applications. Work on React/TypeScript frontends (offline PWAs using IndexedDB/DexieJS and Workbox) and Scala/Play backends with PostgreSQL. Deploy on AWS via Kubernetes. Mentor engineers, collaborate in product-focused cycles, and thrive in a fast-moving startup environment.

Design and build features across a React/TypeScript frontend and Go backend for real-time dispatch systems. Implement WebSocket-driven tracking, GIS integrations, multi-tenant architectures, performance and state management improvements, production debugging, and collaborate with Product and Operations to deliver agency commitments.

Senior CRM systems full stack engineer to design, develop, integrate, and maintain Salesforce and Salesforce Marketing Cloud solutions. Build ETL pipelines, AWS microservices, and integrations, provide tier-3 support, lead testing/UAT, document requirements, and train teams while ensuring code quality and deployment processes.

Design, develop, and maintain full-stack web applications using Java/Spring Boot backends and Angular frontends. Build RESTful APIs, write clean code, collaborate with cross-functional teams, troubleshoot issues, and participate across the SDLC.

Design, develop, and maintain web applications and RESTful APIs using Java/Spring Boot. Develop and maintain PL/SQL stored procedures and Oracle database logic. Participate across the SDLC, troubleshoot backend and database issues, collaborate with cross-functional teams, and improve development processes and tooling.

Lead consolidation and modernization of two legacy giving marketplace applications into a single scalable stack. Re-architect, refactor, and optimize back end (Java, Spring Boot, Hibernate) and front end (Angular, NgRx, SCSS). Implement features, ensure UI/UX feasibility, address performance and scalability, conduct code reviews, and collaborate with the team to deliver a robust application.

Design, develop, and maintain web applications using Java/Spring Boot backends and Angular frontends. Build RESTful APIs, write clean maintainable code, participate across the SDLC, collaborate with cross-functional teams, troubleshoot full-stack issues, and help improve development processes and tools.