Top Senior Backend Engineer Jobs in Denver & Boulder, CO

Design, build, and scale backend services and integrations for payment, billing, identity, and partner systems. Own API scoping, design, implementation, deployment, and production operations with minimal oversight. Build fault-tolerant systems, data pipelines, and scalable architectures while collaborating with product, design, engineering, and external partners. Contribute to reliability monitoring, observability, automation, technical standards, and mentoring in a distributed team.

Lead design and hands-on development of AWS-based serverless backend and IoT cloud services. Build Python Lambda microservices, REST APIs, telemetry pipelines, and secure AWS IoT Core device communication. Mentor engineers, define architecture patterns, ensure production readiness (monitoring, CI/CD, security), and guide cross-functional integrations and technical roadmaps.

Own backend and product delivery from scoping through production. Design customer-facing backend services, AI agent capabilities, APIs, data models, and system architecture for large unstructured datasets. Lead high-impact technical initiatives independently, maintain engineering quality, shape product direction with founders, and translate customer needs into dependable software. The role requires advanced Python, production-scale backend experience, system design expertise, and a product-minded approach.

Design, build, and optimize scalable backend services, APIs, and data pipelines. Integrate with third-party billing/commerce systems, maintain serverless/event-driven architectures on AWS, ensure security and performance, implement automated tests and CI/CD, mentor engineers, and drive architectural decisions.

Build and scale backend data platforms and services for real-time loan origination and financial reporting. Lead quarterly delivery, guide engineers, define technical plans, collaborate with product and design partners, improve reliability and operational practices, monitor service metrics, participate in on-call support, uphold engineering quality standards, and mentor team members. The role requires developing highly available distributed systems and scalable data pipelines using technologies such as Python, Kotlin, AWS, MySQL, Kubernetes, Spark, and Airflow.

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.

Build and scale backend systems for a high-traffic donor CRM and payments platform. Own performant SQL and realtime querying, optimize payment flows, implement AI agents, and collaborate across product and design to ship resilient, production-grade features at scale.

Lead backend architecture and engineering initiatives for a programmatic advertising platform. Design and optimize high-throughput, latency-sensitive ad-serving and auction systems; integrate SSPs, DSPs, exchanges, and other partners; improve reliability and performance; and guide technical strategy. The role also involves mentoring engineers, conducting code reviews, driving major projects from architecture through production, and collaborating with Product and other stakeholders.

Designs, builds, and maintains secure, scalable FHIR-based backend services and REST APIs for CMS initiatives. Implements DEQM Summary MeasureReport profiles, resource validation, conformance checks, SMART security patterns, and automated tests. Partners on architecture decisions, troubleshoots interoperability issues, supports CI/CD conformance testing, and contributes to technical documentation, code reviews, Connectathons, and implementation testing.

Design, develop, launch, and maintain scalable backend systems and APIs used by merchant and partner integrations. Collaborate with engineers and stakeholders, balance speed with system quality, debug code, conduct code reviews, and write tested, extensible software. The role requires experience with distributed systems, Python or Kotlin, AWS, MySQL, and Kubernetes, along with strong communication and ownership of professional growth.

Design, develop, and maintain scalable cloud-native backend applications using Node.js, React, and AWS services. Build secure, high-performing solutions supporting federal missions, troubleshoot complex issues, collaborate with cross-functional teams, and contribute to agile development. Responsibilities include working with serverless services, databases, CI/CD tools, and modern JavaScript technologies while delivering high-quality software.

Build end-to-end product features with a backend focus: schema and API design, UI work in React/TypeScript, GCP/Terraform infrastructure, CI/CD, DB performance tuning, production ownership, and product decision-making using AI coding tools.

Own backend systems and infrastructure end-to-end, designing, deploying, and scaling performant APIs and services on AWS using Node.js and TypeScript. Deliver reliable production code quickly, establish engineering best practices, make architectural tradeoffs, and collaborate with product engineers and stakeholders. The role emphasizes system ownership, scalability, performance, reliability, and effective use of AI-assisted development tools.

Design and develop the backend of the vCluster Platform using Go and deep Kubernetes expertise. Own features end to end, from technical design through release, while solving complex systems and multi-tenancy challenges. Contribute to open-source projects and Kubernetes community initiatives, build scalable isolation and resource-sharing solutions, and operate autonomously in a fast-growing startup environment.

Develop and enhance backend financial and investment products, integrating with financial institutions and partners. Build scalable web applications and backend services using Node.js, TypeScript, PostgreSQL, AWS Lambda, and Kinesis. Responsibilities include analyzing requirements, implementing maintainable features, testing, troubleshooting production issues, designing scalable schemas, and contributing across the technology stack while primarily focusing on backend development.

Senior Backend Engineer responsible for designing scalable Java Spring microservices, implementing features, resolving defects, and improving backend architecture. The role involves event-driven systems, relational and NoSQL databases, testing, code quality, mentoring engineers, technical leadership, and collaboration with product teams. Engineers will also validate AI-assisted code, promote AI development practices, and work with cloud-native tools across AWS, Docker, Kubernetes, and continuous delivery systems.

Develop and evolve a high-throughput, low-latency US sports betting platform using distributed systems and microservices. Build resilient, scalable services for peak sporting events, collaborate with technical and non-technical stakeholders, contribute to architectural direction, and mentor junior engineers. The role also involves cloud infrastructure, Kubernetes, reliability, concurrency, debugging, and delivery of quality software in an agile environment.

Lead architecture and hands-on development of scalable backend systems and APIs supporting real-time applications at massive scale. Own the full engineering lifecycle, establish standards for reliability and testing, troubleshoot production issues, influence technical roadmaps, collaborate cross-functionally, and mentor engineers. The role requires deep backend development, distributed cloud systems, system design, automated testing, and technical leadership experience.

Design, develop, and maintain scalable backend services, REST APIs, server-side applications, and database systems. Improve performance, reliability, monitoring, and security; integrate third-party services; write tested code; troubleshoot production issues; and contribute to code reviews and engineering best practices. Collaborate with frontend, DevOps, QA, and product teams while deploying and operating applications using cloud infrastructure, Docker, and CI/CD pipelines.

Design, build, and maintain scalable backend services, REST APIs, server-side applications, and database systems. Improve performance, reliability, security, monitoring, and logging; integrate external services; write tested code; review implementations; troubleshoot production issues; and collaborate with frontend, DevOps, QA, and product teams. The role also involves Docker, CI/CD, cloud deployments, and potentially Kubernetes, infrastructure as code, and event-driven systems.

Build and operate Python backend services, REST APIs, clinical data models, and batch or event-driven pipelines. Work with FHIR and HL7 healthcare data to support reliable integrations, reporting, analytics, and AI workflows. Establish data quality, validation, governance, lineage, monitoring, and auditability practices. Lead architectural discussions, review implementations, mentor engineers, and collaborate with clinical, product, analytics, and AI teams.

Design, build, test, and operate scalable backend services and APIs. Lead complex projects, make architecture and reliability tradeoffs, improve observability and incident response, collaborate cross-functionally, influence technical direction, mentor engineers, and drive durable improvements to production systems and developer experiences.

Owns delivery of backend money movement and card ledger systems, leading engineers through complex problems and ambiguity. Collaborates with product, design, analytics, and engineering stakeholders; defines scalable technical solutions; supports system availability, monitoring, on-call operations, code quality, and engineering standards. The role also includes mentoring and developing team talent while building highly available distributed systems for Affirm’s financial products.

Designs and scales high-performance backend web services and ETL pipelines supporting tens of thousands of transactions per second. Responsibilities include architecting fault-tolerant distributed systems, improving performance, developing monitoring and deployment strategies, collaborating across product and engineering teams, and supporting recruiting and onboarding. The role requires expertise in data-intensive systems, microservices, cloud architectures, and commercial SaaS products.

Build and operate backend APIs, a reusable integration platform, security-tool connectors, MCP capabilities, and event-driven services. Own GraphQL federation, permissions, multi-tenant access, reliability, observability, vendor API resilience, and production operations. Collaborate across engineering, product, and security teams while mentoring other engineers and contributing to technical standards.