Weights & Biases

Weights & Biases is an AI developer platform for building AI agents, applications, and models, used by Microsoft, Meta, Toyota, Canva, and NVIDIA to track experiments, optimize models, and deploy AI applications at scale. Its Models suite covers experiment tracking, hyperparameter optimization (Sweeps), and data visualization (Tables); Training adds serverless RL and supervised fine-tuning for LLMs; Inference provides hosted access to models from OpenAI, Meta Llama, and Alibaba Qwen; and Weave handles tracing, evaluating, and monitoring AI applications in production. A Registry centralizes publishing of models, datasets, and prompts across a team. A free tier is available, with paid plans for teams needing more; exact pricing requires checking the plans page. Good fit for an ML team that wants experiment tracking, LLM app observability, and model deployment in one connected platform rather than stitching together separate tools for each stage.