Head-to-head
MLflow vs Weights & Biases: which one in 2026?
MLflow is an open source AI engineering platform maintained under LF Projects that teams run themselves, while Weights & Biases is a hosted experiment tracking and LLM tracing product now sold as part of CoreWeave Forge. The core choice is owning the server for free or paying for a polished hosted service with published seat and storage limits.
Verdict
MLflow ranks above Weights & Biases in this category for teams that can operate their own infrastructure, because the price is zero and nothing is capped. Weights & Biases is the better fit for small research groups that want a hosted tool with strong visualization and clear tiers. Since Pro is aimed at teams under 50 employees and Enterprise is quoted, larger organizations should price it carefully against a managed MLflow.
MLflow and Weights & Biases side by side
| MLflow | Weights & Biases | |
|---|---|---|
| Price entry | Quoted | $60 per month, billed monthly (Pro) |
| Licensing and cost to start | Apache 2.0 licensed, described on mlflow.org as forever free. You pay only for the infrastructure you run it on. | Free tier at $0 for personal use, then Pro starting at $60 per month billed monthly, with Enterprise on custom plans. |
| Where the server lives | Local or self-hosted with uvx mlflow server or Docker. Managed versions are linked on the site, including Databricks and SageMaker. | Hosted by the vendor on AWS, Azure or GCP, in the United States or a region the customer chooses. |
| Published usage limits | None on the open source code, since limits come from your own database and storage. Managed prices were not published on pages we opened. | Free allows 5 model seats and 5 GB storage a month. Pro allows 10 seats and 100 GB, with extra storage at $0.03 per GB. |
| Experiment tracking and registry | Experiment tracking, model evaluation, MLflow models and a model registry, with SDKs for Python, TypeScript, Java and R. | Run logging with run.log(), gradient watching, Sweeps for hyperparameter search, Tables, Reports, plus an Artifacts and Models registry. |
| LLM and agent tooling | OpenTelemetry tracing, 50+ built-in evaluation metrics, prompt versioning and an OpenAI-compatible AI Gateway with fallbacks. | Weave handles traces, evaluations, a playground and online monitors, started with weave.init and the @weave.op() decorator. |
| Security paperwork | No data handling or certification statement on mlflow.org. Compliance depends on how and where you deploy it. | States ISO 27001, SOC 2 Type 2 and HIPAA compliance, with certificates on request through its Trust Center. |
| Enterprise controls | Access control wording on the site is general. Single sign-on and audit logging are something you build or buy from a managed host. | Enterprise adds single sign-on, customer-managed encryption keys, audit logs, custom roles and private connectivity options. |
| Who owns the product | A community project governed through LF Projects, so no single seller controls the roadmap or the price. | The vendor site says Weights & Biases is now part of CoreWeave Forge, and pricing sits on a CoreWeave page. |
Where each one wins
MLflow wins on
- Costs nothing in license fees and has no seat or storage caps imposed by a vendor.
- Runs wherever you can run Docker, so data can stay entirely inside your own network.
- Supports Java and R SDKs and an OpenAI-compatible gateway in the same open source package.
Weights & Biases wins on
- Hosted from day one, so nobody on your team has to run a tracking server.
- Has Sweeps, Reports and Tables for hyperparameter search and sharing results with non-engineers.
- Publishes security certifications and an enterprise control list that MLflow leaves to your deployment.
Which to pick
Pick MLflow if
You have engineers who can run a server, want zero license cost, or need training data and runs to stay inside infrastructure you already control.
Pick Weights & Biases if
You want hosted tracking running this week, value dashboards and sweeps over server ownership, and a security team wants named certifications to review.
Each tool in context: MLflow, Weights & Biases, and the full Best MLOps Platforms in 2026.
Frequently asked questions
Is MLflow really free compared with Weights & Biases?
The MLflow software is free under Apache 2.0, but you pay for the server, database and storage that run it. Weights & Biases has a free tier for personal use with 5 model seats and 5 GB of monthly storage, and Pro starts at $60 per month billed monthly, as of November 2026.
Can Weights & Biases be self-hosted like MLflow?
The pages we opened describe hosting on AWS, Azure and GCP in the United States or a region the customer chooses, and an Enterprise option to bring your own bucket. A full self-managed server was not described there, so ask the vendor if that is a requirement.
Which one is better for tracing LLM and agent applications?
Both cover it. MLflow offers OpenTelemetry-based tracing, 50+ built-in evaluation metrics and an AI Gateway. Weights & Biases offers Weave with traces, evaluations, a playground and online monitors. MLflow suits teams that want standards-based tracing they host, Weave suits teams that want it hosted.
Does Weights & Biases still exist after the CoreWeave change?
Yes. The wandb.ai site keeps the Weights & Biases name and states it is now part of CoreWeave Forge. The pricing page redirects to a CoreWeave Forge page, and the privacy policy it links to names CoreWeave, so check current plan wording before buying.