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

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.

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.

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.

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

Lead design and implementation of the PSA Liquidity Platform connecting buyers and sellers. Build buyer tooling, matching/ranking engines, and seller experiences. Architect and operate microservices and Kafka-driven systems on Kubernetes/AWS, instrument observability, apply AI tooling across the SDLC, and drive cross-functional delivery from 0-to-1 while owning end-to-end outcomes.

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.

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.

Lead frontend-leaning full-stack implementation work for carrier and enterprise integrations: architect reusable UI and API layers, author RFCs, guide technical delivery, enforce testing and security best practices, and partner with cross-functional teams to scope and ship production integrations.

Design, architect, develop, test, and support scalable full-stack applications for a data catalog platform. Own features end to end, contribute to technical strategy and roadmaps, ensure operational excellence, collaborate across distributed teams, and mentor engineers. Build multi-tenant systems supporting high data volumes and near-real-time analytics while applying AI-assisted development practices.

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.

Design, implement, and maintain scalable serverless backend services and responsive Next.js front-end components. Build data scrapers and integrations, improve CI/CD and IaC, mentor junior engineers, and collaborate with product and clients to solve complex compliance problems.

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 evolve Humana’s NBA Action Library and Command Center using React, TypeScript, Node.js, PostgreSQL, and Kafka. Develop accessible front-end experiences, REST APIs, data models, integrations, automated tests, and reliable state-driven workflows. Collaborate with product, design, and platform teams to deliver secure, scalable software supporting action creation, governance, versioning, preview, and publishing.

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

Build end-to-end cybersecurity platform features across React, Express, Go microservices, and PostgreSQL. Develop vulnerability management, compliance, security training, and task management experiences; create resilient integrations; implement multi-tenant architecture, RBAC, audit trails, testing, monitoring, and production reliability. Mentor engineers, guide architectural decisions, and contribute to scalable cloud infrastructure and incident response.

Build and maintain Alpaca Connect developer-platform experiences using TypeScript, React, and Go. Improve onboarding, app management, compliance review, publishing, consent, and permissions workflows. Design APIs and integrations with identity, account, trading, and market-data systems while creating secure, auditable self-service tools. Own features from design through production and collaborate with Product, Design, Compliance, Support, Partnerships, and Platform teams.

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.

Lead front-end modernization and deliver full-stack features using React, .NET, PostgreSQL, and cloud technologies. Build accessible, performant applications and design systems; extend APIs, optimize SQL, contribute to Kafka pipelines, and improve testing, observability, CI, and security. Use AI coding agents for migrations, refactoring, and test generation while applying strong engineering judgment. Collaborate with product, UX, DevOps, and stakeholders to deliver reliable healthcare payment-integrity software.