The creator of Walmart’s internal vibe-coding tool is leaving the company for AI start-up Pydantic.

In a memo reviewed by Business Insider, Michael Pfaffenberger wrote to colleagues that he was leaving Walmart a year after growing Code Puppy from 1,000 users to more than 75,000. The tool will continue to be supported by his colleagues at Walmart.

Code Puppy, based on the Pydantic AI library, was created by Pfaffenberger, a distinguished engineer in Walmart’s Global Tech group. The AI coding assistant helps developers write, edit, test, and manage software using natural-language instructions.

“I’m filled with joy that I was able to create…