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

Lead design and build of an AI-native marketing platform: integrations, multi-agent orchestration, UIs, tooling, analytics, CI/CD, auth/multi-tenancy, and production AI agents to automate marketing workflows and drive adoption across teams.

Owner of end-to-end ecommerce features: design, implement, and maintain scalable backend services and performant React/Next.js frontends. Integrate payment gateways and procurement systems (PunchOut), mentor engineers, uphold code quality, and improve platform stability across Node.js, MySQL, and MongoDB.

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.

Design and build a high-performance, AI-native web trading experience for sophisticated retail traders. Ship core trading workflows (order entry, positions, blotter, watchlists, alerts), implement trustworthy AI UI patterns, collaborate with backend engineers on low-latency contracts, and iterate quickly with users and stakeholders to deliver end-to-end product features.

Build end-to-end full-stack AI features on a Ruby on Rails backend and React frontend, design and run experiments (A/B tests and AI evaluations), implement AI infrastructure for reliable LLM inference, and iterate quickly to scale production-ready LLM-powered products.

Join the Entefy team as a Senior Full Stack Engineer to build a scalable full stack application enhancing digital interaction for global clients.

Lead and contribute to an agile scrum team to deliver scalable web application features within sprints. Complete user stories, troubleshoot issues, design and implement complex software solutions, mentor developers, and maintain system architecture, SDLC adherence, and technical documentation. Must meet DHS EOD and fitness requirements.

Lead design and delivery of consumer-facing web applications for school stores and book clubs. Build front-end experiences with React, contribute backend Python work, design APIs and data models, implement testing and monitoring, mentor engineers, and improve development processes across the full software lifecycle.

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.

Own end-to-end growth features across the stack (TypeScript/Node.js backend, React frontend) to drive acquisition, conversion, retention and monetisation. Design architecture, run A/B experiments, instrument metrics, use AI-assisted tools in engineering workflows, mentor juniors, and iterate rapidly with PMs and designers.

Design, build, and maintain backend services, data processing, REST APIs, and Electron-based thick client desktop applications. Ensure secure, scalable client-server architectures, process structured data at scale, support containerized development and automated build pipelines, collaborate with designers, and mentor junior engineers while following Agile best practices.

The Senior Full-Stack Engineer will develop new features and improve existing functionality, collaborate with the product team, and resolve bugs while influencing architectural decisions.

The Senior Full-Stack Engineer will build end-to-end features, create APIs, write requirement documents, and learn Rust while improving product experiences for users.

The Senior Fullstack Engineer will lead projects, mentor engineers, and build user-facing SaaS products using React, TypeScript, Node.js, GraphQL, and MongoDB, focusing on team collaboration and effective trade-off decision-making.

As a Senior Fullstack Engineer, you'll develop a no-code platform, build UIs and backend services, and improve conversation analysis workflows using AI technologies.

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

Design, develop, and deliver fullstack web solutions, optimize platforms, mentor engineers, and manage product features from ideation to launch.

Design, build, and operate end-to-end features across a React frontend and Node.js/TypeScript backend. Implement secure, performant APIs, model and optimize PostgreSQL data, deploy and monitor services on AWS, improve engineering standards through code reviews and testing, troubleshoot production issues, and contribute to scalable system architecture in a distributed team.

Own and implement end-to-end product features across the stack (React/TypeScript front end, Ruby on Rails backend, relational DBs, GCP infra). Design APIs and data models, ensure performance and reliability, integrate AI/LLM-powered features, collaborate with product/design/clinical teams, perform code reviews, and mentor junior engineers.

Design, build, and maintain production-grade .NET web applications and APIs on Azure. Own full-stack delivery from data models and SQL to front-end components, CI/CD, testing, and architecture. Collaborate with product and delivery teams, participate in code reviews, and ensure secure, observable, well-tested services.

Build and ship full‑stack growth experiments end-to-end to improve acquisition, activation, engagement, and monetization. Collaborate with product, design, and analytics, analyze experiment results, iterate quickly, and contribute to experimentation platform and growth infrastructure while balancing speed, quality, and long-term maintainability.

Senior full‑stack engineer responsible for building production-quality Salesforce platform capabilities, integrations (MuleSoft, REST/SOAP), AI-enabled tooling (Claude plugins, MCP servers), CI/CD, and reusable libraries. Mentor engineers, run architecture/code reviews, and collaborate cross-functionally to deliver scalable, secure cloud-native solutions using Python, LWC, Apex, and AWS.

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.

The Senior Fullstack Engineer will deliver software products, collaborate with product and business teams, lead technical practices, and ensure high-velocity iteration on a mobile advertising platform.

The Senior Full-Stack Engineer will develop claims monitoring tools and backend services, collaborate with other engineers, and influence the product architecture in a health insurance startup.