Why we replaced LangChain with the raw Anthropic SDK in production

LangChain was the right answer in 2023. It abstracted away a messy ecosystem of half-baked provider APIs, gave you a unified LLM interface, and let you stitch agents together with a few dozen lines of Python. We used it everywhere — including in production on Vettio, our AI recruitment platform. In April 2026, we ripped it out. This post is about why we made that call, what replaced it , and the metrics that justified the migration. The symptoms LangChain's abstractions started leaking the momen