Weights & Biases / wandb.ai
AI/ML experiment tracking, model registry, and evaluation platform that helps teams track ML experiments, compare model versions, collaborate on training runs, and evaluate LLM outputs.
Pricing
Free
Free plan
Yes
Category
Developer Tools
Platforms
3
Free plan
Yes
API access
Yes
Open source
Yes
Platforms
3
Weights & Biases (W&B) is the most widely adopted ML experiment tracking platform — used by ML researchers and engineers at major AI labs, academic institutions, and enterprise ML teams to track training runs, compare model versions, and collaborate on ML development.
Experiment tracking is W&B's foundational capability — logging metrics (loss, accuracy, custom KPIs), hyperparameters, model weights, and system metrics for every training run automatically with a few lines of Python code. Runs are searchable, comparable, and shareable across teams without manual logging infrastructure.
Weave is W&B's LLM observability and evaluation product — tracing LLM application calls, evaluating model outputs on custom metrics, and tracking evaluation results across model versions. As teams shift from classical ML to LLM applications, Weave extends W&B's tracking into LLM quality management.
Model Registry provides a central repository for model versions with metadata, training provenance, and deployment status — enabling ML teams to manage the model lifecycle from research through production with audit trail and governance.
Artifacts provides versioned storage for datasets and model files — linking training data versions to model versions so the complete training provenance (data + hyperparameters + code + results) is reproducible and auditable.
With users at OpenAI, DeepMind, NVIDIA, and thousands of academic institutions, W&B validates across the most sophisticated ML environments globally.
Weights & Biases AI runs as ml platform software built around data and text workflows. Users typically start with a prompt, upload, or connected data source, and the underlying model handles the heavy lifting before returning a result you can refine or export. It's available on python, cli, and web, with API access for teams that want to embed it into their own products.
The capabilities that matter most for teams evaluating Weights & Biases AI.
Automatic logging of training metrics, hyperparameters, model weights, and system resources for every run — enabling comparison, reproducibility, and collaboration across ML training experiments.
Traces LLM application calls and evaluates outputs on custom quality metrics — extending W&B tracking from classical ML to LLM application quality management.
Centralised versioned model management with training provenance, metadata, and deployment status — providing lifecycle governance from research experiment through production deployment.
Free plan (unlimited projects for individuals). Teams $50/user/month. Enterprise custom.
Model
Freemium
Starting price
Free
Free trial
No
MLflow (covered) provides open source experiment tracking with model registry. Neptune.ai (rank 668) provides competing ML tracking. Comet ML provides experiment tracking. Azure ML provides experiment tracking within Azure ML platform.
A side-by-side look at the closest alternative in this category.
Key facts about model providers, platforms, and team support.
Model Provider
W&B
Platforms
Python, CLI, Web
Deployment
SaaS, Open Source
Integrations
PyTorch, TensorFlow, Hugging Face, LangChain, 50+ frameworks, API
Team Collaboration
Yes
Launch Year
2023
Compliance signals and data-handling notes as reported by the vendor.
SOC 2 Type II. ISO 27001. GDPR compliant. HIPAA eligible. Enterprise data handling agreements.
ML training metrics and model artifacts processed on W&B's cloud or self-hosted infrastructure. Enterprise deployment options available for sensitive model and data requirements.
Editorial Verdict
Weights & Biases is the definitive AI ML experiment tracking platform for research and engineering teams wanting comprehensive training run logging, model version management, and LLM evaluation in one platform.
Last verified July 24, 2026.
Free plan (unlimited projects for individuals). Teams $50/user/month. Enterprise custom.
Free plan (200 hours compute, individual). Team $49/user/month. Scale custom. Enterprise custom.
SOC 2 Type II. ISO 27001. GDPR compliant. HIPAA eligible. Enterprise data handling agreements.
SOC 2 Type II. GDPR compliant. On-premise deployment option. Enterprise data handling agreements.
ML training metrics and model artifacts processed on W&B's cloud or self-hosted infrastructure. Enterprise deployment options available for sensitive model and data requirements.
ML training metadata processed on Neptune's cloud infrastructure. On-premise deployment available for data-sensitive organisations. Training data remains in customer infrastructure.
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