Top Senior Backend Engineer Jobs in Denver & Boulder, CO

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.

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.

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.

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.

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.

Build reusable backend platforms and developer-facing tooling for performance testing, analysis, reporting, and AI-assisted engineering workflows. Enable service teams to independently incorporate performance testing into development and CI workflows through self-service capabilities, documentation, templates, diagnostics, and guidance. Partner with engineering teams, influence adoption, generalize solutions, and provide expertise on complex performance challenges.

Design and implement backend services, modernize legacy systems into microservices, ensure strong testing and production observability, and collaborate with Product and Engineering teams. The role requires independent project ownership, strong system design, AI-assisted development using tools such as Claude or Cursor, effective communication with nontechnical stakeholders, and adaptability in an ambiguous, fast-changing environment.

Senior backend engineer responsible for designing and implementing new features, scaling and optimizing the platform, improving Postgres and Elasticsearch performance, fine-tuning LLMs, and making architectural decisions. Collaborate with engineering team, take ownership of features, write performant, maintainable code, and help shape product and infrastructure for data-intensive applications (NLP, search, indexing).

Leads the design, development, and maintenance of complex backend software systems. Owns significant features end to end, builds scalable APIs and services, ensures code quality and performance, contributes to architecture and technical direction, mentors engineers, and collaborates with cross-functional teams. The role requires extensive C# and .NET experience, insurance industry expertise, microservices, cloud databases, automated testing, and containerized environments.

Design, develop, and maintain scalable, high-performance backend and middleware services on the JVM using Java and Spring/Spring Cloud. Build and enhance microservices, work with AWS and Docker, implement SQL/noSQL solutions (MySQL, Elasticsearch), use Git-based source control and JIRA, collaborate across engineering, design, and QA, and mentor teammates while following best practices and Agile methodologies.

Design and scale Cohere’s Model Vault backend and inference platform. Lead architecture for authentication, deployments, billing, metering, customer lifecycle, and cloud control-plane services. Build reliable distributed systems with strong guarantees for security, privacy, consistency, isolation, observability, and failure recovery. Drive technically complex initiatives from threat modeling and architecture through implementation, production rollout, operations, and iteration at enterprise scale.

Build, maintain, and scale e-commerce backend services using Python and Django. Develop REST APIs and features for catalogs, inventory, carts, checkout, orders, payments, and accounts. Integrate third-party services, optimize databases and performance, implement security controls, write tested code, resolve production issues, and collaborate on architecture, planning, reviews, deployment, and CI/CD.

Design and implement scalable backend services for MoneyGram’s core transaction and API platforms. Responsibilities include architecture, microservices, APIs, event-driven systems, integrations, cloud development, CI/CD automation, testing, deployment, operational excellence, and engineering standards. The role collaborates with product, engineering, and QA teams, mentors junior engineers, leads complex technical solutions, and influences technical direction in an agile environment.

The Senior Software Engineer will design and develop backend systems and APIs, mentor other engineers, and resolve complex integration challenges in healthcare technology.

Design, implement, and maintain scalable, secure, high-performance backend systems and public-facing APIs. Collaborate with Product and Data Science teams, lead initiatives improving efficiency and system performance, and support customer satisfaction. Work may involve distributed systems, pricing engines, identity management, authentication, authorization, API versioning, deprecation, and rate limiting.

Own technical direction and complex projects for Tempo, Grafana’s distributed tracing backend. Build and optimize ingestion, storage, query, metrics, and API components; improve performance, scalability, reliability, and operational excellence. Collaborate across product and engineering teams, write design documentation, participate in on-call and incident response, mentor engineers, and contribute to the open-source Tempo project.

Owns core backend computation services that produce correct, reproducible, traceable, and auditable financial results. Designs configuration-driven architectures, data-intensive services, and set-based warehouse computations. Requires strong Python, SQL, data modeling, system design, reliability, isolation, and testing expertise. Provides technical leadership through design reviews, engineering standards, and mentorship while partnering with data, AI, and product teams.