Software Engineer, Core Services

Our mission is to automate coding. The first step in our journey is to build the best tool for professional programmers, using a combination of inventive research, design, and engineering. Our organization is very flat, and our team is small and talent dense. We particularly like people who are truth-seeking, passionate, and creative. We enjoy spirited debate, crazy ideas, and shipping code. About the Role As a Software Engineer on the Core Services team at SpaceXAI, you'll own the critical shared services that sit between our product surfaces and the infrastructure layer: auth, webhooks, and the backend systems that power agent workflows. SpaceXAI is redefining how developers write code, and your work is what makes that possible at scale. You'll build the systems that every product team depends on, ensuring they are reliable, well-abstracted, and ready for whatever comes next. Example projects include... • Owning authentication: designing and implementing a scalable auth architecture that secures one of the most widely-used developer tools in the world. • Powering the agent backend: owning the infrastructure behind Cursor's agent workflows, optimizing for end-to-end performance and reliability as agents become central to the developer experience. • Building a robust webhook server: handling high-throughput event delivery with proper retry semantics, dead-letter queues, and observability so external integrations just work. • Hardening SCM integrations: building resilient abstractions over source control providers so Cursor stays rock-solid regardless of third-party conditions. • Driving end-to-end agent reliability: partnering with the client and inference teams to improve the full path from user action to agent response, closing the loop on one of the hardest problems in AI-powered development. You may be a fit if • You have experience building and operating critical backend services, especially auth systems, API gateways, or webhook infrastructure. • You've worked on agentic products or infrastructure and have strong opinions on reliability and performance of complex multi-step systems. • You care deeply about clean abstractions, well-defined service contracts, and making it easy for other engineers to build on top of your work. • You have strong software engineering fundamentals and enjoy owning the full lifecycle of production services. • Experience with authentication/authorization frameworks (OAuth, JWTs, RBAC), event-driven architectures, or building developer-facing platform services is a plus. Applying If there appears to be a fit, we'll reach out to schedule 2-3 short technicals. After, we'll schedule an onsite in our office, where you'll work on a small project, discuss ideas, and meet the team. #LI-DNI