Top Senior Backend Engineer Jobs in Denver & Boulder, CO

Build and operate backend services for licensing, entitlements, provisioning, access control, multi-tenant administration, MSP/MSSP workflows, audit logging, and notifications. Design reliable cloud-native systems using Docker, Kubernetes, and relational databases, while contributing to observability, incident response, documentation, testing, and platform security. Collaborate across engineering, product, and design teams and mentor less experienced engineers.

Build backend APIs, GraphQL services, ETL pipelines, event-driven systems, and distributed infrastructure for cybersecurity workflows involving vulnerability intelligence, EDR validation, deception, tripwires, and autonomous defense. The role includes production reliability, monitoring, incident response, debugging, customer-facing security features, and collaboration with engineering and product teams. The engineer will also mentor less experienced developers and ensure security automation is safe, explainable, and reversible.

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.

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.

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 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.

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.

Designs, develops, deploys, and operates scalable Go and Python microservices in distributed production environments. Responsibilities include API design, Kubernetes deployment, monitoring, scaling, troubleshooting incidents, system architecture, security, testing, code reviews, and continuous improvements to development processes and infrastructure. The role requires end-to-end service ownership, strong Linux and Docker expertise, observability knowledge, and experience with reliability, performance, and CI/CD practices.

Design, build, test, and maintain backend services and APIs powering the insurance platform. Integrate payments, documents, and data providers, improve system stability, performance, and scalability, mentor team members, and participate in architectural decisions and agile ceremonies.

As a Senior Backend Engineer at DuckDuckGo, you'll lead backend projects, mentor engineers, and develop AI-enhanced features for the company's privacy-centric product line.

Design and implement secure, scalable backend services for speech inference and audio processing. Optimize networking, transcoding, latency, memory, and distributed compute orchestration. Measure and improve system performance, debug complex networking/scheduling/HPC issues, customize services for customers, and partner with Product to deliver features end-to-end.

Design, build, and operate payment services for card processing, refunds, reconciliation, and processor integrations. Develop scalable Kotlin and Java Spring Boot APIs, optimize PostgreSQL schemas and SQL, and implement idempotency, retries, webhooks, audit trails, and reconciliation. Respond to payment incidents, conduct root cause analysis, collaborate cross-functionally, review architecture and code, and mentor engineers. The role requires strong distributed-systems, payments, PCI DSS, debugging, and production operations experience.

Build and operate scalable backend services for connected devices, including device connectivity, telemetry ingestion, health monitoring, command and control, and data pipelines. Collaborate with firmware, mobile, and product teams on APIs and workflows. Use AWS, microservices, streaming systems, observability tools, and AI coding agents to deliver reliable features, participate in incident response, and improve automation and engineering practices.

Lead the architecture and implementation of scalable conversational AI systems and backend services. Own projects from ideation through execution, shape the engineering roadmap, design RESTful APIs and business logic, integrate external partners, evaluate ML-driven results, and optimize platform scalability. The role also includes technical leadership, mentoring, code reviews, cross-functional collaboration, and product-focused decision-making.

Own significant product areas from customer problem discovery through solution definition, prototyping, shipping, measurement, and iteration. Build AI-powered prototypes and production products using tools such as Claude and Cursor, engage directly with customers and commercial stakeholders, lead small squads, influence product direction, and contribute to an AI-native product engineering culture.

Lead and deliver quarterly goals for a backend team; guide engineers through ambiguous problems; collaborate with product, design, and analytics; identify and resolve project and technical issues; ensure operational availability and on-call readiness; set code and design quality standards; and mentor and develop team members.

Own and scale production backend systems using Ruby on Rails, PostgreSQL, Sidekiq, APIs, microservices, queues, and distributed architectures. Diagnose and improve reliability, security, performance, observability, testing, and deployment practices. Integrate third-party services, collaborate with product, data, design, and frontend teams, and modernize inherited systems while maintaining delivery speed. The role requires strong production ownership, pragmatic technical judgment, and comfort working remotely in a fast-moving startup.

Build and own scalable payments infrastructure for card issuing, transaction processing, and settlement. Design reliable integrations with Stripe, banking partners, and internal platforms using .NET, C#, Azure, DDD, CQRS, and event-driven architectures. Improve system reliability, observability, performance, security, and compliance while mentoring engineers and contributing to technical direction. Apply AI-assisted development across coding, testing, debugging, and engineering workflows.

Own and evolve the backend and Go networking engine for a consumer VPN product. Responsibilities include stabilizing production systems, developing account, subscription, server-selection, and WireGuard APIs, integrating payment and analytics platforms, improving security, testing, observability, documentation, and CI/CD, and collaborating with mobile, infrastructure, product, and operations teams.

Design and deliver LLM-powered, agentic AI systems to automate customer support and compliance. Build scalable, secure backend infrastructure in Python and Go, integrate third-party models/APIs, implement grounding and guardrails, and measure performance. Lead end-to-end projects, mentor engineers, conduct code reviews, and participate in on-call and incident response to improve resolution times and reduce operational costs.

Build and optimize high-performance backend systems for an xOT security platform using Rust. Participate across development lifecycle, design scalable microservices, integrate third-party devices and data providers, incorporate AI tools, and improve observability and reliability through testing, debugging, and peer review.

Lead backend and full-stack work on the Payments team, building multi-gateway integrations (Stripe, PayPal), payment APIs, and customer payment UIs. Ensure secure, compliant (PCI-DSS) payment flows, reliability, observability, and scalability across AWS/Kubernetes microservices. Partner cross-functionally to design architecture, implement settlement/reconciliation, and maintain high availability.

Lead the architecture, development, deployment, and reliability of scalable APIs for Afresh’s flagship AI ordering product. Partner with product, account management, and engineering teams to deliver integrated solutions, support the existing iPad application, and shape future product direction. Drive projects from conception through launch, enforce testing and release best practices, mentor junior engineers, participate in Agile ceremonies, and provide constructive code reviews.