Weights & Biases ranks #2 in MLOps & Experiment Tracking AI search.

Weights & Biases (W&B), founded in 2017 and headquartered in San Francisco, CA, is an AI developer platform offering end-to-end tooling for machine learning and LLM application development. Its two core product lines—W&B Models (MLOps) and W&B Weave (LLMOps)—cover experiment tracking, hyperparameter optimization, artifact versioning, model registry, LLM tracing, evaluation, agentic observability, and serverless fine-tuning. Trusted by over 1,000 organizations including OpenAI, Meta, NVIDIA, Microsoft, Toyota, and Canva, W&B is embedded in 20,000+ open-source repositories and used by more than 1 million AI engineers. In May 2025, W&B was acquired by GPU cloud provider CoreWeave (Nasdaq: CRWV) for a reported ~$1.7 billion, becoming the software layer of CoreWeave's integrated AI cloud platform.

Weights & Biases is an AI developer platform comprising W&B Models (experiment tracking, hyperparameter sweeps, artifact versioning, model registry), W&B Weave (LLM tracing, evaluation, agentic observability, guardrails, online monitoring), W&B Inference (hosted open-source foundation model API), and W&B Training (serverless RL and SFT fine-tuning). A unified SDK enables one-line integration with all major ML frameworks. The platform serves as a system of record across the full AI development lifecycle for both model builders and LLM application developers.