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

Develop and deploy customer-focused web, mobile, and backend applications across the full software stack. Design major features, contribute to architecture decisions, conduct code reviews, and ensure secure, high-quality implementations. Collaborate with stakeholders and cross-functional teams using Agile and SDLC practices. Manage version control, CI/CD, environments, and releases; maintain automated test coverage and perform root-cause analysis. Build and optimize relational data solutions using SQL Server, including complex queries, stored procedures, and performance tuning.

Build and ship customer-facing products across backend services, APIs, data models, React web interfaces, and Android point-of-sale applications. Learn unfamiliar platforms quickly, collaborate with product and design, deliver resilient code, and own testing, instrumentation, on-call support, and cleanup. The role emphasizes 0-to-1 product development, customer-focused decision-making, rapid experimentation, and using AI tools to improve development velocity and quality.

Build scalable, data-intensive products from the ground up, focusing on Java/Kotlin backend services, REST or GraphQL APIs, data access, and React/TypeScript interfaces. Responsibilities include architecture, performance optimization, testing, observability, production troubleshooting, technical documentation, and end-to-end feature ownership. Collaborate with data, reporting, design, and product teams while using AI-assisted development tools to accelerate delivery.

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.

Leads technical vision and strategy for Affirm’s Marketplace, Search, Ads Platform, and consumer experiences. Designs scalable full-stack platforms, guides architecture and technical excellence, coordinates initiatives across engineering teams, mentors engineers, and drives reliable delivery of customer-focused products across iOS, Android, and Web.

Own the specification, design, and implementation of features for FareHarbor’s large-scale web application. Collaborate with product team members, develop scalable and performant full-stack solutions, improve automated testing, resolve technical challenges, and participate in code reviews. The role requires strong Python and JavaScript skills, experience with front-end and back-end frameworks, relational databases, performance optimization, and agile development.

Own end-to-end full-stack feature development across React/TypeScript interfaces and Elixir backend services for spacecraft modeling, simulation, and ground-control software. Drive architecture, technical debt reduction, performance, reliability, testing, API design, and production deployment. Mentor engineers, establish coding standards, collaborate with product, design, QA, operators, and astrodynamics teams, and deliver complex data-dense, real-time applications.

Develop and optimize high-scale Adobe Commerce ecommerce platforms using PHP, JavaScript, Node.js, GraphQL, REST, and MySQL. Separate business logic from presentation layers, improve database and caching performance, build CI/CD validation, monitor production systems with New Relic, and create endurance load tests. Integrate identity, payment, and tax systems while mentoring junior engineers and leading offshore teams.

Lead technical direction and delivery for the Acquisition & Onboarding full‑stack team. Build and maintain mobile (React Native/native) and web experiences, backend services at scale, and operational tooling. Drive architecture, mentor engineers, ensure reliability/monitoring/on‑call readiness, collaborate with product and design, and improve dev processes, testing, and release practices to impact conversion and retention.

Owner of Vannevar's authentication and authorization platform: build tenant-isolated auth systems, self-service user/group/permission admin UI, tooling to visualize and validate access, feature-flag and platform management interfaces, and shared authorization capabilities across products.

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.

Lead backend TypeScript development and maintain services used by ~5M users. Contribute to full-stack features, code reviews, architecture discussions, mentor engineers, and collaborate with PM/design to build React-based web and mobile experiences.

Develop and maintain Java applications, RESTful services, and Angular frontends using Spring Boot and NgRx. Deploy applications to cloud platforms, practice TDD, manage CI/CD with Jenkins, and work with Oracle and PostgreSQL databases. Participate in agile processes, collaborate with cross-functional teams, mentor engineers, and independently lead technical initiatives and feature delivery.

Build and scale Geolava’s spatial intelligence products across frontend and backend systems. Design APIs, data models, and LLM agent workflows; own features from design through deployment, monitoring, and iteration. Collaborate with product, design, research, and engineering teams to deliver reliable, polished solutions. The role requires strong product judgment, autonomy, production Python experience, full-stack TypeScript and React expertise, cloud infrastructure knowledge, and familiarity with agent loops, RAG, MCP, and geospatial technologies.

Build and scale Calendly’s AI Notetaker and meeting recap platform. Responsibilities include developing features, designing service-oriented architecture, contributing to scaling initiatives, collaborating with Product and Design, reviewing code, improving engineering practices, participating in agile ceremonies, mentoring teammates, and supporting on-call operations.

Build and maintain secure, scalable full-stack applications for third-party customers. Develop React interfaces, RESTful and GraphQL APIs, authentication systems, and integrations with relational and non-relational databases. Containerize and deploy applications using Docker, Kubernetes, AWS, GitLab CI/CD, and Helm. Ensure DISA STIG and OWASP compliance, participate in code reviews, guide junior developers, document integrations, and serve as the API integration subject matter expert.

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.

Design, develop, and support scalable full-stack, cloud-native applications using Next.js, TypeScript, .NET, Python, AWS, and Kubernetes. Build AI-enabled solutions involving generative AI, LLMs, intelligent assistants, RAG, and workflow automation. Collaborate with architects, product teams, and clients, contribute to architecture and Agile delivery, troubleshoot production systems, establish observability practices, review code, and mentor junior engineers.

Design, develop, test, document, deploy, and support scalable full-stack applications using React, C#/.NET, and Hack. Build backend services, APIs, integrations, and AI-enabled capabilities including LLM workflows. Participate in Agile planning, code reviews, troubleshooting, client communication, and software delivery while applying modern architecture, DevOps, CI/CD, and automated testing practices.

Build and support consumer-facing full-stack features for an energy-saving platform. Responsibilities include developing TypeScript/React frontend and Python backend functionality, owning critical product flows, collaborating with product and analytics teams, working with cloud and database technologies, implementing UI and API monitoring, and participating in code reviews and agile development processes.

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.

Develop and maintain scalable backend applications, microservices, APIs, integrations, and production-ready client-facing features. Ensure systems are secure, documented, tested, and performant while collaborating with product, engineering, and business stakeholders. Translate business goals into technical architecture, estimate scope and timelines, and contribute across the technology stack in a remote, cross-disciplinary environment.

Design, implement, and maintain cloud-native full-stack software to migrate, preserve, and make large volumes of government records searchable and accessible. Build Section 508-compliant frontends and secure backend APIs, follow API-first and CI/CD practices, defend against vulnerabilities, mentor engineers, and collaborate with cross-functional teams to deliver reliable, performant systems.

Design, build, and optimize scalable cloud and web software with focus on infrastructure, performance, and hardware integration for IoT devices. Collaborate with hardware teams to ensure connectivity and high availability, implement new features, and improve system efficiency.

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