About

Nelson Elhage is a systems software engineer, compiler architect, and AI researcher, currently working on mechanistic interpretability of large language models at Anthropic.

Throughout his career, he has built foundational developer infrastructure and low-level systems. At Stripe, he was a founding engineer of the Sorbet typechecker for Ruby; earlier at Ksplice (acquired by Oracle), he developed zero-downtime Linux kernel hot-patching technology. He is also the creator of legendary open-source developer tools including livegrep (real-time regex code search across massive codebases) and reptyr (reparenting running processes across terminal sessions).

On his long-running technical blog Made of Bugs (blog.nelhage.com), he publishes rigorous, masterclass-level essays exploring systems debugging methodology, structured concurrency, SMT solvers (Z3), CPU microarchitecture, and how expert engineers build accurate mental models of complex software.