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

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.

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.

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.

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.

Build and maintain full-stack analytics and data visualization products, contributing to architecture, APIs, data pipelines, query optimization, front-end experiences, and AI/ML capabilities. Own initiatives from concept through production, improve reliability and performance, collaborate with product and UX teams, contribute to CI/CD, mentor engineers, and establish technical standards across the organization.

Build and maintain full-stack features across a Ruby on Rails monolith and Go microservices. Develop candidate portals, partner integrations, I-9 workflows, adjudication tools, asynchronous vendor pipelines, and AI-powered document and automation features. Own work end to end, including testing, code review, deployment, monitoring, and major user experience paths. Work with PostgreSQL, REST APIs, webhooks, OAuth, SFTP, and server-rendered frontends.

Build and scale Cresta’s no-code conversation intelligence platform across the frontend and backend. Responsibilities include creating visual workflow editors, backend services and APIs, data models, storage layers, and scalable systems using React, TypeScript, Python or Go, Postgres, ClickHouse, and Elasticsearch. Collaborate with product, design, and AI/ML teams to deliver intuitive experiences for non-technical users while improving performance, reliability, security, and maintainability.

Design, build, and maintain backend services in TypeScript for millions of users; develop full‑stack features with React/React Native; participate in code reviews; provide technical leadership, mentorship, and architecture guidance; collaborate with PM and design; use monitoring/metrics and Agile practices to deliver scalable, user-focused products.

Build scalable full-stack applications integrating healthcare insights with browser-based and Windows EHR systems. Develop products using FHIR and HL7 interoperability standards, collaborate on technical roadmaps, and implement performant solutions. Mentor junior engineers, conduct code reviews, make technical decisions, and partner with engineering, product, and business stakeholders using Agile processes.

Lead end-to-end design, development, and delivery of full‑stack features; drive architecture and code reviews; coordinate engineering work, write design docs and tests, and participate in Agile ceremonies. Must have blockchain/crypto experience.

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.