Company Overview: Sustainment is an AI-native software platform that helps US-based manufacturers easily find and work with the critical suppliers they need to build and manage their supply chains. Our vision is to reimagine American manufacturing as a hyperconnected, secure, and resilient ecosystem of local and regional suppliers who can more easily connect, interact, and do business with the industry and government customers that rely on them. We are a dual-use technology platform that supports both DoD and commercial customers in pursuit of our vision. ROLE OVERVIEW We need a Staff Software Engineer to set technical direction and ship fast. You are a hands-on individual contributor with Tech Lead responsibility. You own the hard architectural calls, write production code, and make the engineers around you faster and better. We are scaling. Your job is to help us grow without breaking what works. RESPONSIBILITIES • Lead technical design for major features and own the architecture of our ABP-based applications: module boundaries, shared libraries, and the conventions other teams build on. • Ship production full-stack code at a high standard, including the hardest and most ambiguous problems. • Own the quality end-to-end • Raise engineering standards through code review, design review, and direct mentoring. • Set the team's .NET standards and enforce them in code review and CI. • Build secure-by-design systems, including for AWS GovCloud and government customer environments. • Own reliability, performance, and observability of what you ship. Own failures and fix root causes. • Evaluate tools, frameworks, and methods, and make the call. • Plan and lead .NET and ABP major-version upgrades across our services while feature work continues. • Translate customer and business needs into clear technical priorities with the Director of Engineering and Product. • Document decisions so the team can execute without you in the room. QUALIFICATIONS • 8+ years of professional software engineering, including multiple years owning architecture of production systems. • Proven record of leading technical delivery across a team without formal authority. • 5+ years building production systems in C# and ASP.NET Core. You know the request pipeline, dependency injection lifetimes, and async behavior well enough to debug them under load. • Strong EF Core and PostgreSQL experience: migration strategy across environments, query plans, indexing, and concurrency control. • Production experience with ABP Framework is strongly preferred. Deep experience with the same patterns in another .NET framework is a reasonable substitute if you can learn ABP quickly. • You have found and fixed .NET performance problems in production with tools like dotnet-trace, dotnet-counters, or Datadog APM. • Working proficiency in Angular and TypeScript, enough to ship features end to end. • Experience with distributed systems, cloud infrastructure (AWS), containers, and CI/CD. • Secure coding discipline and experience in regulated or high-assurance environments. • Clear written and verbal communication. You can brief engineers and executives. • Ability to obtain and maintain a US government security clearance. Certain programs may require US citizenship. • Early-stage startup or SaaS experience is a plus. OUR STACK C#, ASP.NET Core, ABP Framework, EF Core, Angular, PostgreSQL, Kafka (Amazon MSK), Docker, Kubernetes, Terraform, AWS (including GovCloud), GitLab, Datadog Sustainment offers a competitive benefits package for full time employees including medical, dental, vision, paid time off, company holidays, and 401K matching. Sustainment is proud to be an equal opportunity employer. We provide employment opportunities without regard to age, race, color, ancestry, national origin, religion, disability, sex, gender identity or expression, sexual orientation, veteran status, or any other protected class. Applicants must be authorized to work for ANY employer in the U.S. We are unable to sponsor or take over sponsorship of an employment Visa at this time. Sustainment participates in E-Verify.