Listed alphabetically. A tool is ranked by its reviews once it has 3.
| Tool | Reviews | Lowest paid plan | Free plan | Free trial | Public API | Runs on | Main features |
|---|---|---|---|---|---|---|---|
 HeliconeRouting and monitoring for reliable AI apps. | ReviewsNone yetWrite one for Helicone | Lowest paid plan$79per monthPro, as of November 14, 2026 | Free planNot confirmed | Free trial7 days | Public APIYes | Runs onNot confirmed | Main features
|
 OpikAn end-to-end AI observability platform to test, ship, and improve agentic systems. | ReviewsNone yetWrite one for Opik | Lowest paid plan$19per monthPro Cloud, as of November 14, 2026 | Free planYes | Free trialYes | Public APIYes | Runs onNot confirmed | Main features
|
 TraceloopTraceloop turns evals and monitors into a continuous feedback loop so every release gets better. | ReviewsNone yetWrite one for Traceloop | Lowest paid planSee plans | Free planYes | Free trial14 days | Public APINot confirmed | Runs onNot confirmed | Main features
|
 W&B WeaveObservability and continuous improvement for production agents. | ReviewsNone yetWrite one for W&B Weave | Lowest paid planNot confirmed | Free planNot confirmed | Free trialYes | Public APINot confirmed | Runs onNot confirmed | Main features
|
From each tool's own website. “Not confirmed” means we couldn't confirm it there, not that the tool doesn't have it. Each tool's page says when its facts were checked.
How this list is made
A tool is listed here only when we've confirmed on its own website that it has a free trial. Tools we couldn't confirm it for are left out, even if they may have it. Vendors can't pay for a place on this list. Add a tool we missed