Top Staff Software Engineer Jobs in Denver & Boulder, CO

Lead design and implementation of Headway's insurance systems (eligibility, pricing, matching, claims). Build data-intensive, ML-powered platforms and automation, mentor engineers, write high-impact code, and improve accuracy and reliability across state and payer complexity to scale insurance-covered therapy.

Lead technical strategy and architecture for Affirm Bank's cloud, data, vendor integrations, and operational tooling. Design, build, and operate high-stakes systems end-to-end, own incident response, vendor selection, and the Bank↔Affirm Inc integration boundary. Ensure examiner-ready documentation, compliance, reliability, and observability while mentoring engineers and pushing AI-assisted engineering practices to increase velocity and product safety.

The Principal Engineer will lead technical direction across multiple teams, design architecture for financial systems, mentor engineers, and drive multi-year transformations in the Money Group.

As a Staff Software Engineer, you'll design, build, and test Gusto's core platform services, mentor engineers, and collaborate with various teams to solve complex engineering problems.

Lead the development of front-end architecture for spacecraft modeling software, drive cross-functional initiatives, mentor engineers, and influence product strategy.

Lead backend engineering for cloud-native, event-driven data pipelines and customer integrations (especially EHRs). Evolve core data models and APIs, improve scalability and reliability, mentor engineers, define best practices, and drive end-to-end testing and AWS-based solutions.

Design and implement Kotlin backend services and end-to-end systems for Toast POS device management. Lead technical designs, estimations, performance optimization, cross-team collaboration, and software quality practices including modern testing and observability. Mentor peers and drive product roadmap alignment with product, hardware, and QA stakeholders.

This role involves leading web platform initiatives, mentoring senior engineers, architecting web applications, and implementing technical strategies for improved performance.

Build a high-performance, low-latency Rust backend and core AI platform for an AI-native trading experience. Implement streaming responses, tool orchestration, caching, secure APIs (auth, rate limits, auditing, tracing), and safe trading action infrastructure (previews, confirmations, idempotency, audit logs). Partner with product and frontend to enable AI-native UX and translate business domain requirements into secure, resilient platform primitives.

Lead full‑stack development and architecture for Spark’s broker platform. Deliver customer‑facing features, partner with product/design, mentor engineers, resolve technical debt, and set engineering standards while using AI developer tools.

Design and develop software solutions enhancing user experience for Governance features, contribute to open-source software, communicate technical designs, and support team quality through reviews.

Lead design and operation of test infrastructure at scale: test orchestration, smart selection, parallel sharding, flaky-test detection, observability, SLOs, and on-call. Define technical strategy, drive cross-team projects, mentor engineers, and reduce test feedback time to accelerate engineering velocity.

Lead and build a new Trust & Safety engineering domain: design and implement systems to detect and mitigate fraud, billing anomalies, and credential abuse. Architect product and operational solutions, mentor engineers, define processes, and deliver scalable, auditable safety tooling across internal and external workflows.

Lead and deliver software solutions, oversee full-stack architecture, mentor engineers, and drive cross-functional initiatives for spacecraft modeling and control platforms.

Develop and manage high-performance back-end systems, design secure APIs, optimize performance in cloud environments, conduct testing, and manage ML model lifecycles.

Own and modernize the governance domain (auth, roles/permissions, orgs, billing) as a Staff-level backend IC: set architecture, refactor for scale and AI-native workflows, write critical-path code (70-80%), mentor engineers, and partner with product to deliver enterprise-grade governance and compliance features.

Design, build, deploy, and operate a high-concurrency, resilient configuration and publishing platform. Lead cross-team projects, set technical direction, improve engineering productivity, optimize performance, and maintain end-to-end ownership of distributed systems at scale.

Lead full‑stack development for Gusto's PEO Benefits product: design and build benefits shopping, plan recommendation flows, carrier integrations, automation agents, and MCP tools; scale Ruby/Rails and JavaScript/React systems; mentor engineers; drive multi‑quarter, cross‑functional projects from spec through launch and iteration; collaborate with Product, Data, Design, and Platform teams to deliver customer‑facing features.

The role involves owning the architecture and technical direction of Payment Rails infrastructure, designing high-reliability systems for global payment processing, and leading cross-functional collaborations to create efficient, compliant solutions. Responsibilities also include mentoring team members and enhancing operational excellence through AI-driven improvements.

Lead architecture and technical direction for Payments platform, building scalable, fault-tolerant distributed systems, defining roadmaps, ownership of production reliability, cross-functional partnership, and mentoring engineers to improve platform quality and scalability.

Own reliability, monitoring, and incident response for AI infrastructure; build automation and CI/CD tooling; manage Kubernetes/Docker production workloads; partner with infrastructure, security, and compliance; improve observability and documentation; develop internal full‑stack tooling in Go or Python.

Lead architecture and multi-year technical strategy for financial data pipelines and reporting. Design and deliver backend services in Go, ensure accuracy, timeliness, and auditability of financial data, and partner with Finance/Accounting/Tax to translate regulatory requirements into scalable systems. Mentor senior engineers and set architectural standards across Financial Engineering.

Join MongoDB's Query Execution team to improve the database's core execution engine, build high-performance query features, and mentor team members. You will drive roadmap initiatives and ensure production-ready code for complex analytical workloads.

Lead design and evolution of SentiLink's data platform for fraud detection. Architect scalable batch and streaming pipelines, improve reliability, performance, and observability, set engineering standards, mentor engineers, drive cross-team technical initiatives, participate in production support/on-call, and evaluate build-vs-buy and emerging technologies.

Design, build, test, and iterate on benefits renewal workflows across frontend and backend. Scale Ruby on Rails and JavaScript/React systems, mentor engineers, drive cross-functional projects end-to-end, implement experimentation, and collaborate with product, design, data, and platform teams to deliver reliable, customer-focused features.