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ToolWeights & Biases (CoreWeave)/10 trustVerified
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Weights & Biases

The ML experiment-tracking standard, now with Weave for LLM tracing and evals.

Acquired — still operating

acquired by CoreWeave

Visit official site →

About

Weights & Biases is the long-standing standard for ML experiment tracking: metrics, hyperparameters, artifacts, and model registry, with the wandb/wandb client MIT-licensed (~11k stars). Weave (wandb/weave) extends it to LLM tracing and evaluations.

Closed SaaS platform (acquired by CoreWeave). Free tier available. If you already track ML experiments in W&B, Weave is the natural LLM extension; greenfield LLM-observability shoppers usually pick Langfuse or LangSmith.

What it can do

  • Experiment tracking: metrics, params, artifacts
  • Model registry and versioning
  • Weave: LLM tracing and evaluations
  • Sweeps for hyperparameter search
  • Reports and collaboration

Setup

  1. Sign up at wandb.ai.
  2. pip install wandb and run wandb login.
  3. Wrap training runs with wandb.init().
  4. For LLM tracing: pip install weave and use @weave.op() decorators.

Prerequisites

W&B account (free tier); API key.

Use cases

codedataautomation

Works with

Generic APIAny agent (.md)

Trust score — 8/10

/10 trustVerified

Scored 8/10 (verified tier). The established ML-tracking standard (~11k stars, MIT client, active), official site live, Weave covers the LLM surface. Docked because the platform is closed SaaS (now under CoreWeave) and the issue count is very high — though that reflects scale. Verified tier.

★ 11,276 GitHub stars

How the trust score is built

Full methodology →
Adoption · stars/downloads, log-scaled vs peers
7.7/10
Maintenance · recency, releases, issue load
8.2/10
Openness · license + docs
9.7/10
Manual review · sanity read + red-flag check
9.0/10
  • · 11,276 GitHub stars (log-scaled vs catalog peers)
  • · last push 1d ago; 18 releases/12mo; 1007 open issues
  • · manual review: the ML experiment-tracking standard; Weave adds LLM tracing; very high issue count reflects scale; license: MIT (client); platform closed SaaS

Sources

Every fact above was checked against these sources. Where a claim comes from the provider and couldn't be independently verified, the text says so.