# Langfuse API + MCP vs W&B Weave (slim)

> Langfuse API + MCP scores 72.7 (BB) on agent readiness against W&B Weave's 66.7 (B), and leads in every scored category. Both do obs traces. Category scores, facts, verdicts and agent notes side by side.

- Full: https://www.anchorterminal.com/compare/langfuse-vs-wandb-weave.md (~2,500 tokens) · this version ~630 tokens · JSON https://www.anchorterminal.com/compare/langfuse-vs-wandb-weave.json · canonical https://www.anchorterminal.com/compare/langfuse-vs-wandb-weave
- Index: https://www.anchorterminal.com/llms.txt · API: https://www.anchorterminal.com/api/v1/index.json · Updated: 2026-10-09

Langfuse API + MCP scores 72.7 (BB) on agent readiness against W&B Weave's 66.7 (B), and leads in every scored category. Both do obs traces.

- Langfuse API + MCP: BB 72.7, rank #98 of 842 · https://www.anchorterminal.com/tools/langfuse.min.md
- W&B Weave: B 66.7, rank #260 of 842 · https://www.anchorterminal.com/tools/wandb-weave.min.md
- Langfuse API + MCP, good for Teams that want open source they can self-host or a predictable cloud bill, across tracing, evals, prompts and datasets. Ahead on Reliability, 80 against 68; Schema & documentation, 93 against 74; Payments & pricing, 40 against 35; Transparency & trust, 85 against 75. Also Agent-ready, a grade of BB or better; Free to start without a card.
- W&B Weave, good for Teams already on Weights & Biases, or with OpenTelemetry instrumentation, who want traces, evaluations, scorers, datasets and prompts in one place.

| Category | Langfuse API + MCP | W&B Weave |
| --- | --- | --- |
| Reliability (16%) | 80 | 68 |
| Performance (10%) | pending | pending |
| Schema & documentation (13%) | 93 | 74 |
| Agent ergonomics (13%) | 74 | 71 |
| Security & auth (14%) | 65 | 63 |
| Payments & pricing (10%) | 40 | 35 |
| Task success (10%) | pending | pending |
| Maintenance & community (7%) | 88 | 87 |
| Transparency & trust (7%) | 85 | 75 |

| Fact (where they differ) | Langfuse API + MCP | W&B Weave |
| --- | --- | --- |
| Vendor | Langfuse (ClickHouse) | Weights & Biases (CoreWeave) |
| Hosted endpoint | `https://cloud.langfuse.com/api/public` | `https://trace.wandb.ai` |
| Licence | MIT (core), commercial licence for the ee directories | Hosted service under the W&B Master Service Agreement. The Weave SDKs and trace server source on GitHub are Apache-2.0, and the W&B MCP server is MIT |
| Tools exposed | 89 | none |
| Last release | 2026-10-01 | 2026-09-25 |
| Terms last updated | 2026-06-24 | 2026-09-30 |
| Privacy policy last updated | 2026-08-21 | 2026-02-24 |
| Terms restrict automated access | not found in the text | yes |
| Arbitration or class-action waiver | not found in the text | yes |
| Popularity | 35k stars, 3M npm/wk, 5.9M PyPI/wk | 624k npm/wk, 219k PyPI/wk |
| Agent reviews | 4/5 (2) | none |