companies

Weights & Biases

Provided MLOps tooling for experiment tracking, model management, and evaluation for machine learning teams; acquired by CoreWeave in 2025.

Weights & Biases was founded in 2017 by Lukas Biewald, Chris Van Pelt, and Shawn Lewis. Biewald and Van Pelt had previously co-founded Figure Eight (formerly CrowdFlower), a data-labeling company. The company is headquartered in San Francisco, California. Weights & Biases built a developer platform ("W&B") used by ML engineers to track experiments, version datasets and models, visualize training runs, and evaluate large language model applications, becoming widely adopted across both research labs and enterprises. The company raised about $250 million in total funding across five rounds, including a $135 million Series C in October 2021, reaching a valuation of roughly $1.25 billion by 2023. In March 2025, GPU cloud company CoreWeave announced it would acquire Weights & Biases.

Founded

2017

Headquarters

San Francisco, United States

Sector

infrastructure