Weights & Biases

license

Apache-2.0(OSI, SDK/client repo wandb/weave)

source

public

backend

commercial(W&B SaaS platform hosts traces/evals

eval+tracing-client

OSS

Apache-2.0 OSS instrumentation SDK (@weave.op tracing + eval scoring) but the trace store / dashboards / monitoring backend is the proprietary W&B SaaS platform, open-core, calibrated below MLflow O5 (fully-OSS core) and at/with Langfuse O4 (OSS core + commercial backend).

• https://github.com/wandb/weave recorded 2026-06-04

  Apache-2.0 license on the Weave SDK repo; LLM logging/tracing/eval toolkit