Top Senior Backend Engineer Jobs in Denver & Boulder, CO

Architect and operate Affirm’s large-scale Amazon EKS compute platform, including cluster lifecycle, node management, autoscaling, shared components, infrastructure automation, workload safety policies, observability, cost and capacity optimization, and self-service workflows. The role drives technical strategy, mentors engineers, partners cross-functionally, and participates in on-call incident response.

Build and operate Affirm’s AI platform, including LLM and MCP gateways, agent runtimes, evaluation services, and governance controls. Design highly available backend systems, manage identity, quotas, routing, caching, reliability, observability, and security for AI workloads. Own projects from design through launch and on-call, establish engineering standards, collaborate across teams, mentor engineers, and help scale AI systems into production.

Build and enforce workload safety standards across Affirm’s Amazon EKS fleet. Responsibilities include Kubernetes resource management, workload isolation, disruption handling, cluster capacity analysis, policy automation, production debugging, incident response, fleet-wide rollouts, technical leadership, mentoring, and measuring infrastructure impacts on availability, latency, risk, and cost.

Own and deliver highly available, low-latency backend identity systems supporting consumer onboarding, authentication, and verification. Lead quarterly team goals, guide engineers through ambiguous problems, collaborate with product and design partners, monitor system reliability, improve engineering standards, support on-call operations, and mentor team members. The role requires designing and launching distributed systems at scale using Python or Kotlin, AWS, MySQL, and Kubernetes.

Build and ship backend features end-to-end using Ruby on Rails and SQL. Lead complex technical projects, solve architecture challenges, establish standards, conduct meaningful code reviews, resolve high-risk bugs, document systems, collaborate across engineering teams, and mentor junior engineers.

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 evolve high-scale backend capabilities for GitLab’s container registry. Drive architecture, performance, reliability, security, APIs, testing, and operational readiness. Mentor engineers, influence technical direction, participate in incident response, and collaborate asynchronously across product, infrastructure, data, frontend, and security teams. Integrate and evaluate agentic AI systems in production engineering workflows while promoting responsible and effective use.

Build and operate highly scalable Go backend services and data infrastructure for the AT Protocol ecosystem. Scale systems to support hundreds of millions of users, hundreds of millions of events, petabytes of NVMe storage, thousands of CPU cores, and tens of terabytes of RAM. Responsibilities include developing mission-critical services, managing production operations, and working with databases, distributed systems, operating systems, networking, and storage technologies.

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.

Designs, develops, and supports scalable Java microservices using Spring Boot and Google Cloud. Responsibilities include SQL and data pipeline development, CI/CD automation with Jenkins, infrastructure as code using Terraform, unit testing, code reviews, production incident resolution, root-cause analysis, agile execution, and mentoring engineering teams.

Build and operate backend services and asynchronous workflows that provision customer accounts, assets, and product entitlements. Own projects from design through production support, ensuring reliable retries, idempotency, observability, testing, and recovery from failures. Collaborate with licensing, Product, administration, partner, and customer-facing teams to improve onboarding and activation paths. Investigate operational issues, address root causes, document systems, and contribute to code reviews and technical problem solving.

Design and own backend infrastructure for a privacy-first AI memory platform. Responsibilities include multi-tier memory storage, secure multi-tenant isolation, real-time APIs, caching, LLM integrations, retrieval systems, synchronization, monitoring, deployment pipelines, and production reliability. The role requires close collaboration with ML engineering and product teams while owning architecture, infrastructure, testing, security, and operational troubleshooting.

Leads architecture, development, and operation of Python-based AWS backend and IoT services. Designs Lambda microservices, REST APIs, event-driven workflows, telemetry pipelines, databases, device communication, and infrastructure as code. Provides hands-on technical leadership through coding, design and code reviews, mentoring, cross-functional planning, security practices, testing, CI/CD, monitoring, incident response, and roadmap 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.

Design and build scalable backend services and APIs for a real estate software platform. Develop clean, maintainable Java code on AWS, collaborate with frontend, design, and product teams, and solve performance and scaling challenges. The role requires strong problem-solving skills, debugging ability, data structures and algorithms knowledge, startup experience, and comfort using AI-assisted coding tools.

Develop and maintain Ruby on Rails backend systems supporting solar development, value evaluation, and loan servicing. Responsibilities include writing and reviewing code, maintaining CI/CD pipelines, solving complex domain problems, collaborating with Product and company experts, shaping architecture and technical direction, and improving engineering processes as the company scales.

Design and maintain scalable backend systems in a distributed microservices architecture. Build RESTful APIs, integrate third-party vendors, optimize SQL and NoSQL databases, and implement messaging, observability, CI/CD, and cloud infrastructure practices. Lead engineering initiatives from requirements through delivery, contribute to technical strategy, document systems, and improve reliability, performance, and scalability across user-facing applications.

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.

Design and scale production-grade asynchronous backend systems in Python, including REST/WebSocket APIs, multi-agent LLM workflows, provider-agnostic integrations, and RAG pipelines. Build schemas and migrations, optimize relational databases, instrument services, and own CI/CD from testing through deployment. Establish AI governance around code review, provenance, licensing, security, compliance, and customer data. Drive architecture and product ideas from conception through production.

Build and operate the backend platform for autonomous cybersecurity agents, including durable workflow execution, tool and connector frameworks, safe-change pipelines, tenant isolation, ETL, GraphQL services, observability, audit trails, and distributed systems. Partner with AI researchers and security engineers to productionize agent capabilities across customer environments while enforcing authorization, rollback, quotas, and data protection.

Design, build, and operate scalable backend services for payments, cards, spend management, and compliance. Develop production-quality services and APIs, optimize databases, integrate AI and third-party APIs, and implement secure event-driven architectures. Own features from design through deployment and monitoring, contribute to reliability and CI/CD improvements, participate in on-call rotations, and collaborate with globally distributed engineering, product, compliance, and data teams.

Design and develop scalable backend systems using Kotlin, Micronaut, and Spring. Build RESTful APIs, optimize PostgreSQL and Elasticsearch databases, implement RabbitMQ-based asynchronous processing, integrate AI tools, and create automated tests. Deploy and monitor services on GCP using Docker, Kubernetes, and Terraform. Collaborate cross-functionally, participate in code reviews, troubleshoot performance issues, and deliver reliable backend products.