Top Senior Backend Engineer Jobs in Denver & Boulder, CO

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 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.

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.

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.

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 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.

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.

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.

Lead backend development to scale and harden API infrastructures, implement unit testing playbooks, optimize core algorithms, support migration from Supabase to a robust cloud provider, ensure system reliability and scalability, collaborate with frontend and DevOps, and integrate AI workflows and RPA where applicable.

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).

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.

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.

Lead the architecture, development, testing, and maintenance of scalable backend systems and APIs. Drive technical decisions, code quality, performance optimization, documentation, continuous delivery, and monitoring. Collaborate with product, design, and engineering teams to translate requirements into reliable solutions. Mentor junior engineers, conduct code reviews, resolve complex technical issues, and contribute to agile development and overall technology strategy.

Develop and maintain backend infrastructure for Arbitrum, focusing on distributed systems, blockchain scalability, security, performance, compiler pipelines, SDK frameworks, microservices, databases, and API architecture. Responsibilities include maintaining Nitro Testnode, reviewing code, supporting stakeholders, collaborating with research and security teams, and driving technical roadmaps for high-performance blockchain systems.

Lead architecture and build platform services for GoDaddy's Internal Developer Platform used by 1,000+ engineers. Design high-scale APIs, infrastructure orchestration, and AI-powered developer tooling. Partner with infrastructure, security, and platform teams. Own production systems (performance, reliability, on-call) and drive technical direction to improve developer productivity across APIs, CLI, and UI.

Lead development of scalable backend systems, enterprise API integrations, data migrations, and cloud-native applications for a health technology platform. Build Python services using Flask and AWS serverless technologies, design PostgreSQL-backed systems, ensure security and observability, conduct code reviews, and provide technical leadership. Collaborate with product teams, clients, and stakeholders to gather requirements, make architectural decisions, and deliver complex integrations and software projects.

Build and enhance Judi Health’s scalable healthcare platform using Python, AWS, PostgreSQL, and infrastructure-as-code technologies. Lead features from design through delivery, collaborate with product, design, QA, and engineering teams, provide technical guidance, and serve as a subject matter expert. Work in an Agile/Scrum environment while writing quality code, unit tests, and supporting cross-functional stakeholders.

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.

Build and own the graph layer and RAG architecture enabling agent reasoning over full patient context. Select graph DBs, design query patterns, and ensure temporal coherence. Implement event-driven Kafka pipelines for auditable, immutable agent workflows and enforce ReBAC permissions. Prioritize safety and scalable AI-assisted workflows, participate in spec and plan reviews, and drive architecture decisions.

Architect and build high-throughput backend systems for Filevine’s legal technology platform using .NET, DDD, event sourcing, MartenDB, Wolverine, and PostgreSQL. Own features end to end, including domain modeling, APIs, testing, observability, CI/CD, and production monitoring. Mentor engineers, optimize system resilience and performance, and collaborate with product, UX, and legal experts to translate complex workflows into scalable software.

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.