Weights & Biases

Weights & Biases provides experiment tracking and LLM observability tools for AI developers. W&B Models lets you log experiments, track hyperparameters, visualize training metrics, compare runs, and manage model artifacts across all major ML frameworks. W&B Weave adds tracing, evaluation, and monitoring for LLM applications, automatically logging inputs, outputs, and metadata with support for multi-modal tracking. The platform includes a generous free tier with unlimited tracked hours and projects, with Pro and Enterprise plans for larger teams.