Scale AI is a San Francisco-based technology company that provides data annotation and data labeling services used to train artificial intelligence and machine learning models. In practical terms, Scale AI sits between raw data and finished AI systems: it organizes and manages the human and automated workflows that tag images, text, audio, and video so that AI models can learn from that material. Without accurately labeled training data, AI systems cannot reliably identify objects, understand language, or make decisions.
The company was founded in 2016 by Alexandr Wang, who started it at age 19 after leaving the Massachusetts Institute of Technology. Wang built Scale AI around the idea that high-quality labeled data is the core bottleneck in AI development — that whoever controls data quality controls the pace of AI progress. The company is incorporated under the name Scale AI, Inc.
Scale AI's clients have included technology companies, automotive firms developing autonomous vehicles, and U.S. government agencies including the Department of Defense. Its defense and government work, conducted through a unit sometimes referred to as Scale Federal, has been a notable and growing part of its business, covering applications such as intelligence analysis, autonomous systems, and AI evaluation for military programs.
Beyond labeling, Scale AI has expanded into AI evaluation and model testing — helping organizations measure how well large language models and other AI systems perform before and after deployment. This work, sometimes called "red-teaming" or model benchmarking, has become an increasingly significant part of the company's offering as AI developers compete on model quality.
Scale AI operates as a privately held company and has raised capital from venture investors over multiple funding rounds since its founding, reaching a valuation that placed it among the more highly valued AI infrastructure companies in the U.S. It is primarily known in the industry as the leading commercial provider of training data infrastructure for large-scale AI development.