Top Senior Backend Engineer Jobs in Denver & Boulder, CO

As a Senior Software Engineer, you will develop new products and improve engineering infrastructure while taking ownership of product deliverables and enhancing technical architecture.

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, 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.

The role involves designing and expanding backend systems, mentoring engineers, and executing technical strategies to modernize architecture and improve system performance.

Build and maintain CI/CD pipelines, cloud infrastructure, Terraform automation, database systems, monitoring, and observability on Google Cloud. Support reliability, security, compliance, incident response, and shared on-call operations while applying backend engineering expertise to production services. The role manages PostgreSQL, Redis, BigQuery, Bigtable, and Firestore environments and contributes to disaster recovery and operational tooling.

Develop and maintain backend applications using .NET, C#, Redis, OpenSearch, AWS, and cloud-native technologies. Responsibilities include troubleshooting software issues, optimizing performance and reliability, conducting code reviews, supporting applications, and leading software and process improvements. The role also involves mentoring colleagues, collaborating independently or with teams, and ensuring high-quality software delivery.

As a Senior Back-End Engineer II, you will focus on platform engineering and DevOps, building CI/CD pipelines, managing cloud infrastructure, and supporting database operations.

Design, build, and maintain scalable, secure backend services powering bank accounts, cards, and payments. Own distributed systems, design data models across SQL/NoSQL, build RESTful APIs, improve reliability and observability, participate in code reviews, and collaborate with cross-functional teams to deliver secure, maintainable solutions for millions of users.

Build and operate backend services and production applications incorporating LLMs, machine learning, retrieval, tool use, and agentic workflows. Partner with data scientists to productionize models, develop AI evaluation and observability systems, support clinical and operational data workflows, and improve scalable cloud-native architecture. The role also involves secure data handling, reliability engineering, cross-functional collaboration, and production support for healthcare AI products.

Build and evolve scalable backend systems and APIs for a large SaaS platform. Partner with Product, Design, and QA from ideation through deployment, contribute to microservices architecture, improve testing and observability, identify operational risks, and mentor teammates. The role emphasizes reliable, maintainable solutions, strong collaboration, architectural decision-making, and continuous improvement.

Architect, develop, and optimize backend services and APIs for Lovevery’s global subscription e-commerce and digital parent experiences. Build scalable data models, manage account and subscription systems, checkout, fulfillment, CMS, security, reliability, and performance. Collaborate with Product, Design, and Frontend teams, evaluate vendors, improve engineering standards, CI/CD, and cloud infrastructure, and mentor teammates while using AI-assisted development responsibly.

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.

Design and build scalable backend services, data systems, pipelines, cloud infrastructure, and AI-enabled features for an enterprise SaaS platform. Lead technical projects, improve reliability and security, automate engineering workflows, and collaborate with product, design, and data teams. The role requires hands-on ownership in a fast-moving startup environment, with a focus on distributed systems, architecture, performance, compliance, and operational excellence.

Design, build, maintain, and scale production backend services and integrations. Debug cross-service production issues, lead architecture and technical decisions, mentor engineers, improve engineering standards and tooling, release backward-compatible APIs, implement auto-scaling services, and architect real-time systems for syncing large data volumes.

Lead architecture and implementation for a secure distributed data platform runtime. Design Go-based concurrency, subprocess supervision, inter-service protocols, distributed persistence, and resilient processing pipelines. Debug complex cross-process and network issues, define testing standards, conduct end-to-end integration and resilience testing, participate in on-call rotations, and lead incident post-mortems. Collaborate with product, engineering, and customer stakeholders to refine requirements and deliver production-ready capabilities. Requires up to 25% international travel to the Middle East.

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.

Lead backend development and operate services end-to-end: design, implement, deploy, monitor, and troubleshoot cloud-based back-end systems. Participate in on-call rotation, collaborate with frontend, CloudEng, and product teams, conduct code and security/privacy reviews, and mentor junior engineers.

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.

Design and build scalable backend systems, data pipelines, and cloud infrastructure. Own CI/CD, containerization, databases, and reliability; collaborate with tech leads to deliver secure, production-grade solutions for startups in a fully remote environment.

Design, develop, and maintain scalable Java/Micronaut enterprise frameworks and cloud-native microservices on Azure. Build and deploy services to AKS, create CI/CD pipelines with Azure DevOps, implement batch/asynchronous workflows, integrate messaging systems, optimize databases, and ensure security, observability, and resilience.

The Senior Backend Engineer will lead AI-focused projects, optimize data pipelines, mentor juniors, and enhance customer support through innovative technologies.

The Senior Backend Software Engineer will design and scale backend systems using Python and FastAPI, collaborate with researchers, optimize infrastructure, and implement testing and monitoring systems.

The Senior Software Engineer will enhance backend systems, ensure low latency in transaction processing, and maintain service availability while improving core functionalities.

The Senior Backend Engineer develops core product features in ETL and GraphQL, designs APIs, builds ETL pipelines, and collaborates with frontend teams.

As a Senior Backend Developer, you'll design and maintain high-volume pipelines and databases, implement ETLs for automated abuse-prevention, and develop monitoring solutions while collaborating with teams on safety systems.