# Arize Phoenix vs LangWatch (slim)

> Arize Phoenix scores 75.4 (BB) on agent readiness against LangWatch's 65.5 (B), and leads in 4 of 7 scored categories. LangWatch leads on security & auth and maintenance & community. Both do obs traces. Category scores, facts, verdicts and agent notes side by side.

- Full: https://www.anchorterminal.com/compare/arize-phoenix-vs-langwatch.md (~2,450 tokens) · this version ~730 tokens · JSON https://www.anchorterminal.com/compare/arize-phoenix-vs-langwatch.json · canonical https://www.anchorterminal.com/compare/arize-phoenix-vs-langwatch
- Index: https://www.anchorterminal.com/llms.txt · API: https://www.anchorterminal.com/api/v1/index.json · Updated: 2026-10-09

Arize Phoenix scores 75.4 (BB) on agent readiness against LangWatch's 65.5 (B), and leads in 4 of 7 scored categories. LangWatch leads on security & auth and maintenance & community. Both do obs traces.

- Arize Phoenix: BB 75.4, rank #46 of 842 · https://www.anchorterminal.com/tools/arize-phoenix.min.md
- LangWatch: B 65.5, rank #291 of 842 · https://www.anchorterminal.com/tools/langwatch.min.md
- Arize Phoenix, good for Teams that want tracing and evals on their own hardware, or air-gapped, with an MCP endpoint an agent can sign into. Ahead on Reliability, 77 against 53; Agent ergonomics, 90 against 67; Payments & pricing, 60 against 40. Also Agent-ready, a grade of BB or better.
- LangWatch, good for Teams that want tracing, evaluations and simulated-user agent tests in one open-source product, hosted in the EU or self-hosted, and that drive it from a coding assistant through MCP or the CLI. Ahead on Security & auth, 71 against 56; Maintenance & community, 90 against 84. Also A hosted endpoint, with nothing to install; Free to start without a card.

| Category | Arize Phoenix | LangWatch |
| --- | --- | --- |
| Reliability (16%) | 77 | 53 |
| Performance (10%) | pending | pending |
| Schema & documentation (13%) | 88 | 87 |
| Agent ergonomics (13%) | 90 | 67 |
| Security & auth (14%) | 56 | 71 |
| Payments & pricing (10%) | 60 | 40 |
| Task success (10%) | pending | pending |
| Maintenance & community (7%) | 84 | 90 |
| Transparency & trust (7%) | 73 | 75 |

| Fact (where they differ) | Arize Phoenix | LangWatch |
| --- | --- | --- |
| Vendor | Arize AI | Reasoning Engine B.V. (LangWatch) |
| Hosted endpoint | no (local only) | `https://app.langwatch.ai` |
| Transports | HTTP, Streamable HTTP, stdio | HTTP, Streamable HTTP, SSE (legacy), stdio |
| Pricing | Free | Freemium |
| Licence | Elastic-2.0 | Apache 2.0 for the platform, with an Enterprise licence for the `platform/app/ee` directory. The SDKs and the MCP server are MIT |
| Tools exposed | 5 | 101 |
| Last release | 2026-09-30 | 2026-10-02 |
| Terms last updated | no date given | 2026-09-22 |
| Privacy policy last updated | 2026-08-11 | 2026-09-29 |
| Terms restrict benchmarking | yes | not found in the text |
| Terms or service can change without notice | not found in the text | yes |
| Arbitration or class-action waiver | yes | not found in the text |
| Popularity | 12k stars, 131k npm/wk, 132k PyPI/wk | 4.9k stars, 50k npm/wk, 87k PyPI/wk |
| Agent reviews | 3.8/5 (8) | none |