Top Backend Engineer Jobs in Denver & Boulder, CO

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.

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.

Leads cross-team backend initiatives and technical architecture for GitLab’s Core DevOps platform. Responsibilities include modernizing a monolith, establishing service, API, data, security, testing, and observability standards, guiding Go and Kubernetes practices, supporting Rust adoption, participating in incident response, mentoring engineers, reducing technical debt, and advancing AI-assisted engineering workflows.

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.

Designs, builds, and scales backend services and integrations for payments, billing, identity, and partner connectivity. Sets technical vision and architecture for distributed systems, leads cross-team delivery, manages production rollouts, builds fault-tolerant services and data pipelines, and mentors engineers. The role partners with product, design, and engineering teams to deliver frequent, reliable improvements for Flex’s rent payment platform.

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.

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.

Build and operate Go-based automation for PostgreSQL provisioning, configuration, upgrades, failover, scaling, and decommissioning at GitLab.com scale. Develop a PostgreSQL-as-a-service platform, integrate cloud infrastructure and infrastructure-as-code tooling, improve database performance and reliability, and create safe upgrade automation. The role includes production ownership, architecture leadership, code reviews, documentation, cross-team collaboration, mentorship, and using AI agents in engineering workflows.

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.

Develop and operate backend systems supporting post-transaction processing for Affirm Card. Break down projects, write tested and extensible code, collaborate with product and engineering teams, monitor system health, troubleshoot issues, participate in on-call support, and contribute to code reviews and team development.

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.

Design, build, and operate backend services for Bestow’s insurance platform using Python, Go, Java, and PostgreSQL. Collaborate on technical decisions, integrations, carrier onboarding, and scalable platform capabilities. Mentor engineers through reviews and pairing, improve production reliability and observability, participate in on-call support, and communicate technical decisions in a remote-first environment. Use agentic AI coding tools daily and help establish effective AI-assisted development practices.

Provides cross-team technical leadership for complex backend initiatives, modular architecture, monolith modernization, API and platform standards, production operations, and AI-assisted engineering adoption. Designs shared patterns for services, data, eventing, security, testing, observability, deployment, and reliability. Partners with Product and Engineering leadership, mentors engineers, participates in incident response, and drives technical strategy without formal authority.

Build, test, ship, and operate production backend features with minimal guidance. Design APIs, background jobs, integrations, data models, migrations, and bounded services while maintaining security, performance, observability, and reliability. Review code, improve automated testing, investigate production issues, address technical debt, participate in operational support, and collaborate asynchronously with product, frontend, infrastructure, and security teams. Use AI coding tools responsibly by validating and correcting generated output.

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.

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.

Own and lead the technical direction of a major codebase section while designing, building, testing, documenting, and maintaining secure, scalable API-based decisioning products. Partner with product, engineering, and security teams on agile delivery, troubleshoot production issues, meet SLA requirements, and participate in an on-call rotation.

Build and scale Go backend services for agent quoting, configuration, and application submission. Partner with adjacent teams, resolve partner-specific edge cases, provide architectural leadership, write unit and integration tests, review code, and promote automation, CI/CD, and continuous improvement. The role expects daily use of AI coding tools and ownership of services across distributed systems and microservices environments.

Design, build, and operate backend Go services and smart contracts that mint, burn, bridge, and reconcile wrapped assets across multiple chains. Own end-to-end delivery from smart contract deployment through API design, SLOs, and production rollout. Drive asset migration pipeline improvements, run on-call operations, build observability and runbooks, and mentor junior engineers.

Design and implement secure, scalable backend services for voice agents, integrate AI models and telephony, improve inference, debug concurrent systems, and collaborate with Product to deliver features end-to-end.

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.

Develop, maintain, and optimize mission-critical backend APIs and scalable cloud services for web and mobile clients. Implement secure, high-performance systems, automated tests, observability, and technical documentation. Mentor peers, follow best practices, and support a proof-of-concept launch and fundraising activities as a volunteer contributor.

Build and maintain backend services and APIs, write unit tests, debug and optimize systems, support migration from Supabase to cloud, improve reliability, and integrate AI/RPA workflows while learning under senior mentorship.

Design, build, test, and support EPIC integration solutions across the full interface lifecycle. Gather requirements, resolve integration issues, develop standards and documentation, and provide production support within a remote, volunteer, part-time setup.