# Weights & Biases

> Weights & Biases (W&B) is the AI developer platform that the world's leading machine learning teams use to build, train, and deploy better models faster. Founded in 2017 in San Francisco, W&B provides experiment tracking, model management, and LLMOps tooling used by over 1 million developers - from OpenAI and Meta to Toyota and AstraZeneca. Acquired by CoreWeave in May 2025 for $1.7 billion, W&B is now the software backbone of one of the most important AI infrastructure companies in the world.

- **Founded:** 2017
- **Headquarters:** San Francisco, USA
- **Founders:** Lukas Biewald (CEO & Co-Founder), Chris Van Pelt (Co-Founder), Shawn Lewis (Co-Founder)
- **Team size:** ~300 employees; 45% women, 40% hold PhDs
- **Products:** W&B Models, W&B Weave, W&B Inference, W&B Training, Registry
- **Notable:** Reached 1 million+ registered users by 2024, Achieved 70% adoption among top 100 AI labs globally, Achieved 80% adoption among top 50 universities

## Products & services

- **W&B Models** — Core MLOps platform for experiment tracking, hyperparameter optimization, model registry, and dataset versioning. The foundation product used by over 1 million ML developers.
- **W&B Weave** — LLMOps toolkit for tracing, evaluating, and iterating on LLM applications. Includes cost estimation, hosted inference playground, multi-model comparison, and agent evaluation.
- **W&B Inference** — OpenAI-compatible API providing access to leading open-source foundation models with built-in usage tracking and integration with Weave for evaluation and cost monitoring.
- **W&B Training** — Reinforcement learning post-training infrastructure for large language models. Serverless RL with automatic scaling for multi-turn agentic tasks (public preview).
- **Registry** — Collaborative model and dataset registry for publishing, versioning, and sharing ML artifacts across teams and organizations.
- **Mission Control** — Infrastructure integration layer connecting W&B tooling with CoreWeave's GPU cloud infrastructure (2025 preview).

## Achievements

- Reached 1 million+ registered users by 2024
- Achieved 70% adoption among top 100 AI labs globally
- Achieved 80% adoption among top 50 universities
- Acquired by CoreWeave for $1.7 billion in May 2025
- Named Google Cloud Technology Partner of the Year for Generative AI (2023)
- Named AWS Generative AI Tools Partner finalist (2023)
- Raised $250 million total across 5 funding rounds
- Built a team with 45% women and 40% PhDs
- Co-founder Lukas Biewald previously sold CrowdFlower/Figure Eight for $300M (2019)

## Latest updates

- **2026-01** — Released W&B v0.77 with API key security enhancements, workspace navigation improvements, line plot shading, and media panel sync.
- **2025-09** — Partnership with LG CNS to launch 'Hwangso', a finance-specialized LLM leaderboard.
- **2025-06** — CoreWeave launched three new AI cloud software products at Fully Connected Conference: Mission Control Integration, W&B Inference, and W&B Online Evaluations.
- **2025-05** — Acquisition by CoreWeave completed at $1.7 billion valuation.
- **2025-03** — CoreWeave announced acquisition of Weights & Biases for $1.7 billion.
- **2024-02** — Acquired Sematic to enhance workflow orchestration capabilities.
- **2023-08** — Raised $50 million strategic round from Daniel Gross, Nat Friedman, and Sapphire Ventures at $1.25B valuation.

## Links

- Website: https://wandb.ai
- LinkedIn: https://www.linkedin.com/company/wandb
- Twitter/X: https://twitter.com/weights_biases
- GitHub: https://github.com/wandb
- YouTube: https://www.youtube.com/channel/UCBp3w4DCEC64FZr4k9ROxig

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Profile page: https://yespress.io/weights-biases
Published by YesPress — https://yespress.io
Last updated: 2026-04-20