Sr. Software Engineer (Platform + AI)

At Lumen Dynamics , we believe change happens on purpose. We champion the power and potential of nonprofits, igniting next-level impact with the team and technology built for purpose. Our powerful giving platform and stellar support enable tens of thousands of nonprofits to raise more, recruit more, and retain more, fueling maximum impact and raising the bar on what’s possible for the nonprofit sector. That's why, even as the nonprofit sector sees declines in giving, Lumen Dynamics customers raise more year over year. We're also in the business of creating thriving employees. Join a mission-driven culture built on our core values of Simplify, Care and Act. We know our people are the key to our success, and we're proud to be home to some of the most innovative and skilled individuals in the workforce today. Come feel invigorated and unstoppable with us! The Role As a Sr. Software Engineer on the Platform Engineering team at Lumen Dynamics , you build and own the AI harness our engineering organization runs on—the agentic tooling, orchestration, and evaluation infrastructure that turns frontier models into reliable, everyday engineering leverage in service of our mission to empower nonprofits. You go deep on what makes AI-driven development trustworthy at scale: agent workflows and guardrails, tool and model integrations, prompt and context pipelines, and evals. And you help us use the throughput that unlocks the way it should be used—not just shipping faster, but following through on delivery with real customer feedback, measurement, and iteration until the work makes a meaningful difference for nonprofits. In the near term you’ll also strengthen the systems the platform depends on—our authentication chain (centralized authentication and session management) as we drive toward a unified identity solution, primarily in C#/.NET. But your throughline is the harness: you make every engineer around you faster, and you raise the bar for how Lumen Dynamics builds with AI. What You Will Do Build and own the agentic harness Lumen Dynamics engineering runs on—agent workflows, tool and model integrations, orchestration, and the guardrails and evaluation infrastructure that keep AI-driven development reliable and safe. Use the throughput AI-driven development unlocks to follow through on delivery—ship minimum viable increments, then gather real customer feedback, run A/B tests, measure what shipped, and iterate until it makes a meaningful difference for nonprofits. The work doesn’t stop at the MVP; we use the time AI gives back to deliver the functionality, quality, security, and the rest of the -ilities our industry has always wanted to and rarely had time for. Own cross-cutting AI-platform concerns while standardizing prompt and context pipelines and consolidating local development environments across our products and teams. Keeping token spend efficient without ever trading away quality or completeness. Continually evaluate new models, AI tools, harnesses, and approaches—running rigorous evals and turning the winners into paved-road tooling the whole organization can rely on. Design, build, and own backend services at the core of our platform—in the near term, our authentication chain (centralized authentication and session management), advancing toward a unified identity solution, primarily in C#/.NET. Diagnose and resolve complex technical bottlenecks across distributed services and the AI tooling that sits on top of them, leveraging deep knowledge of debugging and observability tools to keep our SaaS platform fast and reliable. Improve the engineering standards, automation, developer tooling, and AI harness the team relies on. Help the team deliver in a continuous-flow (Kanban) model—keeping work moving, surfacing bottlenecks, and continuously improving how we work, including collaborative practices like mob (ensemble) programming. Use your experience to shape our software and delivery tooling—raising the bar on engineering standards, teaching and learning alongside the organization, and helping us ship better products for the nonprofits we serve. Actively explore, integrate, and help lead the responsible use of AI across the team—shaping Lumen Dynamics ’s AI culture as we lean into it. What You Need to Succeed Genuine AI fluency and hands-on experience building with AI—agents, tools, harnesses, prompt and context pipelines, or evals—not just using AI to code faster. 8+ years of professional software engineering experience building and operating production services—or equivalent demonstrated depth. Strong C#/.NET proficiency is ideal but not a deal breaker. We care most about your ability to own backend services end to end and ramp quickly on our stack; familiarity with the agentic-tooling ecosystem (model APIs, MCP, LLM orchestration) is a strong plus. Experience with foundational platform or distributed systems; authentication, identity, security, MFA, SSO, or session management is a plus. A self-directed, senior-level ownership mindset