Top Backend Engineer Jobs in Denver & Boulder, CO

Lead backend engineering for a high-performance, data-intensive SaaS platform. Responsibilities include defining technical vision, designing scalable and highly available systems, executing technical projects, participating in architecture decisions, monitoring and optimizing services, improving CI/CD and infrastructure, conducting postmortems, mentoring engineers, documenting practices, and aligning with partner teams.

Leads architecture and hands-on development of scalable backend systems and APIs supporting real-time applications. Owns the engineering lifecycle, writes high-performance code, establishes testing and reliability practices, resolves production issues, guides technical roadmaps, collaborates cross-functionally, and mentors engineers. The role requires expertise in object-oriented backend development, distributed cloud systems, automated testing, system monitoring, and technical leadership.

Lead technical vision and strategy for Affirm’s Cards backend engineering organization. Architect scalable and reliable platforms, guide cross-team initiatives, champion AI adoption and engineering excellence, influence technical roadmaps, and mentor engineers through Staff level. The role requires strong architectural expertise, organizational leadership, project management, communication, and cross-functional collaboration.

Own and deliver backend lakehouse infrastructure goals, lead engineers through complex problems, and build highly available distributed data systems. Collaborate with product, design, analytics, and engineering stakeholders; define scalable technical solutions; improve code quality and engineering standards; monitor operational health; support on-call responsibilities; and mentor team members.

Design and scale foundational APIs and backend services for LogicGate’s multi-tenant GRC platform. Build distributed systems using Java/Kotlin, Spring Boot, AWS, databases, caching, and messaging technologies. Improve reliability, observability, performance, testing, and CI/CD practices. Lead technical design reviews, collaborate cross-functionally, mentor engineers, and use AI coding tools to improve development efficiency.

Design, develop, test, deploy, and monitor scalable backend systems for a payroll SaaS product. Build APIs and microservices, collaborate with product and engineering teams, participate in code reviews, and own the full development lifecycle in a continuous delivery environment. The role emphasizes Kotlin, Scala, or Java, cloud platforms, automated testing, relational databases, scalable architecture, and responsible use of AI coding tools.

Lead fraud decisioning engineering initiatives by architecting, building, launching, and maintaining complex backend systems. Drive cross-functional projects from definition through monitoring, write high-quality and resilient code, review technical work, mentor engineers, collaborate with Product, ML, Analytics, and Business teams, and contribute to hiring and interview design.

Develop backend tools and systems that improve batch development, testing, workflow efficiency, and reliability. Collaborate with product, infrastructure, design, and analytics teams; break projects into deliverable phases; build scalable, well-tested code; monitor metrics; support system availability and on-call operations; debug code; conduct reviews; and contribute to engineering growth and hiring activities.

Design and implement backend APIs, microservices, and checkout platform components for Affirm’s financial products. Own system health, improve performance and reliability, collaborate across engineering teams, and contribute to technical standards, tooling, and processes. The role requires developing, testing, and shipping high-quality software at scale while making customer-centric technical decisions.

Build and lead development of high-availability backend services for Affirm’s card loan platform. Design scalable APIs, data models, microservices, and event-driven systems supporting real-time loan attribution, approvals, origination, and refunds. Drive technical strategy, troubleshoot complex performance issues, collaborate with cross-functional teams, and mentor engineers while ensuring long-term system robustness and scalability.

Lead backend engineering strategy for Affirm’s search and recommendation platform. Design and launch highly available distributed systems, guide technical architecture and execution, improve team operations and reliability, establish engineering quality standards, collaborate with product, design, and analytics, and mentor engineers. The role focuses on search, recommendations, consumer shopping experiences, monetization, and scalable platform foundations.

Develop and scale backend streaming and data infrastructure using Kafka, Flink, AWS, Kubernetes, and related technologies. Break down projects, deliver tested software, collaborate with product and engineering teams, monitor system availability, participate in on-call support, debug code, conduct code reviews, and contribute to team development.

Architect, build, and operate large-scale relational and distributed SQL database infrastructure. Responsibilities include database control-plane automation, provisioning, failover, backups, upgrades, zero-downtime migrations, Kubernetes networking, connection proxy optimization, reliability monitoring, capacity planning, and operational support. The role also leads technical delivery, mentors engineers, establishes quality standards, collaborates cross-functionally, and contributes to team roadmap and on-call operations.

Build and operate production-grade Python backend services, APIs, distributed systems, data pipelines, and agentic workflows for an AI observability platform. Own ambiguous projects from prototyping through architecture, testing, deployment, and ongoing operation. Collaborate with product, machine learning, and infrastructure teams, while contributing React front ends when needed. The role requires strong backend depth, distributed-systems expertise, cloud experience, and end-to-end product ownership.

Own and evolve a high-traffic catalog API for satellite imagery. Design backend services and data pipelines in Python, optimize PostgreSQL performance over large geospatial datasets, operate cloud infrastructure, and deliver reliable deployments with automated testing. The role offers significant architectural ownership on a small, autonomous team and involves geospatial standards, scalable services, and production modernization.

Lead backend engineering strategy for Affirm’s international Identity team. Design and launch highly available distributed systems supporting KYC, user lifecycle management, and identity decisioning. Drive technical planning, cross-functional collaboration, operational excellence, monitoring, testing, and on-call readiness. Establish engineering quality standards, influence architecture, mentor team members, and deliver scalable systems using Python or Kotlin, AWS, MySQL, Spark, and Kubernetes.

Lead technical strategy and execution for foundational Trust and Safety systems supporting consumer risk and credit reporting. Design and operate highly available backend systems, improve reliability and monitoring, establish engineering standards, guide complex cross-functional initiatives, and mentor engineers. The role involves ownership of system architecture, technical planning, operational readiness, code quality, and team development.

Build and launch backend identity decisioning systems that validate consumer identity and satisfy KYC regulations. Collaborate with Product, Compliance, Auth, Fraud, Analytics, and engineering teams; decompose projects, write tested and extensible code, monitor system metrics, support availability and on-call operations, debug code, participate in reviews, and contribute to technical decisions and team development.

Build scalable backend services and infrastructure for mobile and web products. Design secure RESTful APIs, architect high-performance systems, apply engineering best practices, estimate and track Agile tasks, mentor teammates, collaborate with clients and engineers, and take ownership of technical solutions.

Design, build, and improve scalable backend systems that collect hard-to-access OSINT; build pipelines and ETL for messy data; collaborate with product and mission teams; mentor engineers and ensure reliable data delivery for DoD workflows.

Lead the technical direction and architecture of the Foundations platform team, owning authentication, authorization, SSO, secrets management, tenancy, and core platform services. Design APIs, drive services through launch, make technical decisions, establish engineering standards, and mentor engineers without formal management authority. Partner with engineering and product leaders to align execution with priorities.

Design, build, and maintain backend services and APIs using Ruby on Rails. Improve performance, scalability, reliability, and write well-tested production code. Collaborate with Product, Frontend, Data Engineering, and QA teams.

Build, architect, and own moderate-to-complex backend components; lead small teams or projects; provide technical guidance and code reviews; deliver end-to-end backend services focused on AI-enabled customer data insights, onboarding, messaging/calling features, and scalable data management for a growing user base.

Design, develop, deploy, and maintain secure, scalable Java and Spring Boot services for a multi-tenant ecommerce SaaS platform. Build REST APIs, optimize MySQL data access, operate AWS workloads, and support CI/CD, observability, testing, and production troubleshooting. Contribute to architecture and technical decisions, mentor engineers, use AI-assisted development tools responsibly, and help maintain PCI DSS compliance.

Design, build, deploy, and maintain secure, scalable Java and Spring Boot services for a multi-tenant ecommerce SaaS platform. Develop REST APIs, optimize MySQL databases, operate AWS workloads, and support CI/CD, observability, testing, and production systems. Contribute to architecture and technical decisions, mentor engineers, troubleshoot issues, and participate in on-call support while ensuring PCI DSS compliance and responsible use of AI-assisted development tools.