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

Design, build, and maintain scalable backend services and APIs for commerce workflows using Python/Django. Improve reliability, performance, and observability, operate AWS deployments, work with PostgreSQL and event-driven architectures (SNS/SQS), modernize legacy systems, and support CI/CD, testing, and production troubleshooting.

Build and ship full-stack features for customer-facing Console and Playground, plus internal tools. Design and maintain APIs and backend services, implement accessible performant frontends, translate product requirements into incremental work, and improve code quality through reviews and design discussions.

Develop and deliver production-ready web experiences for marketing using React, Gatsby, and Tailwind. Build API integrations, maintain a lightweight codebase and design-system components, ensure accessibility, performance, SEO, and multi-region support, participate in code reviews, and help shape tooling and best practices across the team.

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.

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.

As a Senior Software Engineer, you'll design, develop, and maintain full-stack applications, utilizing TypeScript and modern frameworks while collaborating cross-functionally to enhance user experience and performance.

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 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.

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.

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.

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.

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.

Lead architecture and implementation of scalable web applications using NestJS and Next.js. Build and optimize PostgreSQL schemas and queries, implement responsive UIs with Tailwind CSS, integrate LangChain-driven AI features, manage authentication with Clerk, and create end-to-end tests and automation with Puppeteer to ensure launch readiness and reliable user experiences.

Design, build, and scale full‑stack rental systems. Lead frontend architecture and implement complex UIs, integrate and design APIs, optimize performance and accessibility, drive code quality and testing, and collaborate cross‑functionally to deliver scalable microservices on AWS.

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.

As a Senior Fullstack Engineer, you'll architect and build a high-concurrency auction engine, leveraging AI for enhanced user experiences and system reliability.

As a Senior Fullstack Engineer, you'll build financial systems, design lending infrastructure, implement payment integrations, and create user interfaces, ensuring correctness and reliability.

The Senior Full Stack Engineer builds and ships features across frontend and backend systems, working with various frameworks and databases, while collaborating on technical specifications and improving developer experiences.

Design and build responsive web applications and APIs, ensuring secure integration and compliance with government standards in an agile environment.

As a Senior Full-Stack Engineer at ClassDojo, you'll deliver code and features collaboratively, improve systems and practices, and mentor other engineers, all while impacting education for millions of children.

Design and build scalable SaaS solutions, collaborate with other engineers, and ensure quality UI interactions while incorporating user feedback.

Design and maintain federated GraphQL schemas and server-driven UI; build fast, accessible front-end apps with React and TypeScript; develop and optimize GraphQL/SQL backends; operate production services (Kubernetes, observability in DataDog), own releases and on-call rotations; drive testing, CI/CD, technical debt reduction, mentoring, and cross-team coordination.

Lead design, build, and scale GridUnity's cloud SaaS platform. Own end-to-end features, mentor engineers, drive architecture, improve scalability, reliability, security, and data practices while collaborating with product teams.

Embed with brokerage operations to observe and replace manual workflows with auditable automations and UIs. Design, build, deploy, monitor, and run production systems; instrument outcome metrics; collaborate with compliance, security, and domain experts; own full lifecycle including CI/CD, on-call, and incident response.