Weights & Biases

Weights & Biases automatically logs every hyperparameter, metric, and artifact from a training run, making it trivial to reproduce a past result or compare hundreds of experiments side by side. CoreWeave acquired W&B in 2025, pairing the industry-standard experiment tracking layer with CoreWeave's GPU cloud infrastructure — a notable consolidation in the ML infrastructure space, since W&B remains the default tool researchers reach for from OpenAI down to individual grad students.