# Arize Phoenix vs W&B Weave

Arize Phoenix is free, with no paid plan attached. W&B Weave is freemium — a usable free tier with paid plans above it.

| | Arize Phoenix | W&B Weave |
|---|---|---|
| Pricing | Free | Free tier + paid plans |
| Free to start | Yes | Yes |
| Category | AI Models & Local Execution | AI Models & Local Execution |
| Type | LLM Eval & Observability | LLM Eval & Observability |
| Best for | Fully open-source, self-hostable with zero setup via `uvx` (pip/conda also supported) | Agent-native tracing model with sessions, steps, tools and sub-agents as first-class concepts (not generic spans) |

## FAQ

### Arize Phoenix vs W&B Weave: what is the difference?

Arize Phoenix is free, with no paid plan attached and is listed for fully open-source, self-hostable with zero setup via `uvx` (pip/conda also supported). W&B Weave is freemium — a usable free tier with paid plans above it and is listed for agent-native tracing model with sessions, steps, tools and sub-agents as first-class concepts (not generic spans). Both sit in LLM Eval & Observability.

### Is Arize Phoenix or W&B Weave cheaper to start with?

Arize Phoenix is the cheaper starting point: it is free, with no paid plan attached, while W&B Weave is freemium — a usable free tier with paid plans above it. Pricing tiers here come from the catalog, not from a promotional page.

### Which should I choose, Arize Phoenix or W&B Weave?

Choose Arize Phoenix if you need fully open-source, self-hostable with zero setup via `uvx` (pip/conda also supported); choose W&B Weave if you need agent-native tracing model with sessions, steps, tools and sub-agents as first-class concepts (not generic spans). Flocci AI Tools does not rank one above the other — it shows both feature sets side by side and lets the requirement decide.

## Related

- [Arize Phoenix](https://aitools.flocci.in/tool/arize-phoenix)
- [W&B Weave](https://aitools.flocci.in/tool/w-b-weave)
- [Arize Phoenix alternatives](https://aitools.flocci.in/alternatives/arize-phoenix)
- [W&B Weave alternatives](https://aitools.flocci.in/alternatives/w-b-weave)
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Source: Flocci AI Tools — https://aitools.flocci.in/compare/arize-phoenix-vs-w-b-weave

Facts last verified: October 2026