# Best LLM evals and observability tools, ranked by real usage

the week of Oct 25–31, 2026. Canonical page: https://index.devtoolwatch.com/categories/evals-and-observability/

| Rank | Tool | Stars | Downloads/wk |
|---|---|---|---|
| #1 | [SkillSpector](https://index.devtoolwatch.com/tools/nvidia-skillspector/) | 23.7k | – |
| #2 | [Judgeval](https://index.devtoolwatch.com/tools/judgmentlabs-judgeval/) | 1.1k | 80.2k |
| #3 | [A.I.G (AI-Infra-Guard)](https://index.devtoolwatch.com/tools/tencent-ai-infra-guard/) | 7.2k | – |
| #4 | [Langfuse](https://index.devtoolwatch.com/tools/langfuse/) | 36.8k | 9.8M |
| #5 | [Opik](https://index.devtoolwatch.com/tools/opik/) | 23.1k | 709.1k |
| #6 | [promptfoo](https://index.devtoolwatch.com/tools/promptfoo/) | 26.7k | 1.2M |
| #7 | [garak](https://index.devtoolwatch.com/tools/garak/) | 9.8k | 12.9k |
| #8 | [MLflow](https://index.devtoolwatch.com/tools/mlflow/) | 28.6k | 5.2M |
| #9 | [DeepEval](https://index.devtoolwatch.com/tools/deepeval/) | 19.2k | 769.5k |
| #10 | [Arize Phoenix](https://index.devtoolwatch.com/tools/phoenix/) | 12.1k | 158.1k |
| #11 | [Logfire](https://index.devtoolwatch.com/tools/logfire/) | 4.5k | 4.6M |
| #12 | [OpenLIT](https://index.devtoolwatch.com/tools/openlit/) | 2.9k | 88.1k |
| #13 | [LangSmith SDK](https://index.devtoolwatch.com/tools/langsmith/) | 1.1k | 32.1M |
| #14 | [Guardrails](https://index.devtoolwatch.com/tools/guardrails/) | 7.6k | 33.3k |
| #15 | [Braintrust](https://index.devtoolwatch.com/tools/braintrust/) | 29 | 4.2M |
| #16 | [Inspect AI](https://index.devtoolwatch.com/tools/inspect-ai/) | 3.1k | 727.6k |
| #17 | [Evidently](https://index.devtoolwatch.com/tools/evidently/) | 8k | 196.7k |
| #18 | [NeMo Guardrails](https://index.devtoolwatch.com/tools/nemo-guardrails/) | 7.4k | 109.3k |
| #19 | [Ragas](https://index.devtoolwatch.com/tools/ragas/) | 16.2k | 273k |
| #20 | [Laminar](https://index.devtoolwatch.com/tools/laminar/) | 3.5k | 892.3k |

## FAQ

### What is the fastest-growing of the LLM evals and observability tools right now?

SkillSpector ranked #1 among LLM evals and observability tools on the Devtoolwatch Board in the week of Oct 25–31, 2026, with a momentum score of 94 out of 100.

### Which of the LLM evals and observability tools has the most GitHub stars?

Of the LLM evals and observability tools ranked in the week of Oct 25–31, 2026, Langfuse has the most GitHub stars: 36.8k.

### Which of the LLM evals and observability tools is downloaded the most?

LangSmith SDK's main package had the most downloads of the ranked LLM evals and observability tools: 32.1M in the week of Oct 25–31, 2026.

### How does Devtoolwatch rank LLM evals and observability tools?

Every Monday the Board averages four percentile ranks: new GitHub stars from daily snapshots, new stars for the repo's size, added npm and PyPI downloads, and download growth beyond the market. Star spikes without forks, downloads or Hacker News to back them are held back.