What is Weights & Biases used for?

Weights & Biases is an AI developer platform for experiment tracking, model registry and LLM evaluation, with a Weave toolkit for AI applications. It is a good fit for tracking model training runs, evaluating LLM applications and debugging AI agents with traces.

Is Weights & Biases free?

Yes. Weights & Biases has a free plan.

Is Weights & Biases open source?

No. Weights & Biases is proprietary (closed-source) software. Open-source alternatives to Weights & Biases include MLflow, labml and Langfuse.

Can I self-host Weights & Biases?

Yes. Although Weights & Biases is closed source, it can be self-hosted on your own servers, and the vendor also offers a hosted version.

What are some alternatives to Weights & Biases?

Weights & Biases competes with DataRobot, Dataiku and Databricks. For open-source options, see Enlisted's ranked list of open-source Weights & Biases alternatives.

Weights & Biases: features, pricing and alternatives

About Weights & Biases

Weights & Biases, often shortened to W&B, is a platform where machine learning teams track experiments, manage models and evaluate AI applications. It acts as a system of record for training AI models and for building applications on top of them.

Its Weave product covers traces for exploring and debugging AI applications, evaluations, a playground for prompts and models, and monitors that support continuous improvement in production. Solutions pages address use cases such as fine-tuning LLMs, training LLMs, RAG, computer vision, evaluations, AI governance, contact centers and quant trading, across industries from healthcare to the public sector.

W&B is a commercial product with a hosted cloud, and its enterprise pages cover security, deployment and performance, with a pricing page for privately hosted options. It is aimed at ML engineers and research teams, and it is not open source.

Key features

Experiment tracking
Model registry
LLM evaluations in Weave
Traces for debugging AI apps
Prompt and model playground
Production monitors

Good fit for

→Tracking model training runs
→Evaluating LLM applications
→Debugging AI agents with traces

Tags: mlops; experiment-tracking; model-registry; llm-evaluation; machine-learning; observability; ai-developer-tools; saas

Weights & Biases: questions and answers

What is Weights & Biases used for?: Weights & Biases is an AI developer platform for experiment tracking, model registry and LLM evaluation, with a Weave toolkit for AI applications. It is a good fit for tracking model training runs, evaluating LLM applications and debugging AI agents with traces.
Is Weights & Biases free?: Yes. Weights & Biases has a free plan.
Is Weights & Biases open source?: No. Weights & Biases is proprietary (closed-source) software. Open-source alternatives to Weights & Biases include MLflow, labml and Langfuse.
Can I self-host Weights & Biases?: Yes. Although Weights & Biases is closed source, it can be self-hosted on your own servers, and the vendor also offers a hosted version.
What are some alternatives to Weights & Biases?: Weights & Biases competes with DataRobot, Dataiku and Databricks. For open-source options, see Enlisted's ranked list of open-source Weights & Biases alternatives.