Scale AI, Inc.

Scale AI, Inc. is an American artificial intelligence infrastructure and software company headquartered in San Francisco, California, founded in 2016 by Alexandr Wang and Lucy Guo through the startup accelerator Y Combinator. The company began by specializing in data annotation for machine learning and has since expanded into reinforcement learning from human feedback services, evaluation of large language models, and enterprise software for building and deploying AI applications; it employed approximately 1,200 people as of 2025. In June 2025, Meta Platforms acquired a 49 percent non-voting stake in Scale AI for 14.8 billion dollars, and co-founder Alexandr Wang moved into a leadership role at Meta.