Best AI Agent Observability Tools in 2026
Updated
In short: Opik is ranked #1 of 30 as of 3 October 2026, ahead of Langfuse and Arize AX. The best-ranked option with a free plan is Langfuse. The lowest first paid tier on this page is Opik at $19/mo.
When you need visibility into how AI agents behave, observability tools can help you examine prompts, tool activity, sessions, and costs. Compare agent framework support alongside prompt and tool tracing, session replay, and trace retention. Deployment options, free-plan availability, and paid-from pricing offer further points to check against your requirements. Opik and Langfuse lead the ranking, followed by Arize AX and W&B Weave. OpenLIT, Traceloop, Helicone, and MLflow Tracing are also among the first entries. Consider which parts of agent activity you need to inspect and how long trace data should remain available, then weigh those needs against the listed capabilities and access options.
30 ai agent observability tools ranked on what their makers publish — plans and prices, free tiers, platforms and the facts on their own pages.
| # | Platform | Score | Why | From | Free plan | Paid from | Trace retention | |
|---|---|---|---|---|---|---|---|---|
| 1 | Opik | 9.0 | RecognisedAPIDocumented | $19/mo | Yes | 19 /mo | — | View |
| 2 | Langfuse | 8.9 | RecognisedAPIDocumented | $29/mo | Yes | 29 /mo | — | View |
| 3 |  Arize AX | 8.5 | RecognisedAPIDocumented | $50/mo | Yes | 50 /mo | — | View |
| 4 | W&B Weave | 8.5 | RecognisedAPIDocumented | $60/mo | Yes | 60 /mo | — | View |
| 5 |  OpenLIT | 8.3 | RecognisedAPIDocumented | Free | Yes | — | — | View |
| 6 |  Traceloop | 8.2 | RecognisedAPIDocumented | Free | Yes | — | — | View |
| 7 | Helicone | 8.2 | RecognisedAPIDocumented | $79/mo | Yes | 79 /mo | — | View |
| 8 |  MLflow Tracing | 7.9 | RecognisedAPIDocumented | Free | Yes | — | — | View |
| 9 |  Traccia | 7.8 | RecognisedAPIDocumented | $99/mo | Yes | 99 /mo | 30 days | View |
| 10 |  VoltOps | 7.7 | RecognisedAPIDocumented | $50/mo | Yes | 50 /mo | 90 days | View |
| 11 | Maxim AI | 7.6 | RecognisedAPIDocumented | $29/mo | Yes | — | — | View |
| 12 | Galileo | 7.5 | RecognisedAPIDocumented | $100/mo | Yes | 100 /mo | — | View |
| 13 | Agenta | 7.5 | RecognisedAPIDocumented | $29/mo | Yes | 29 /mo | — | View |
| 14 |  LogicGaze | 7.4 | RecognisedAPIDocumented | Free | Yes | — | — | View |
| 15 | SigNoz | 7.2 | RecognisedAPIDocumented | $19/mo | Yes | 49 /mo | — | View |
| 16 |  Arize Phoenix | 6.8 | RecognisedAPIDocumented | — | Yes | — | — | View |
| 17 | LangWatch | 6.8 | RecognisedAPIDocumented | — | Yes | — | — | View |
| 18 | HoneyHive | 6.7 | RecognisedAPIDocumented | — | Yes | — | — | View |
| 19 | LangSmith | 6.7 | RecognisedAPIDocumented | — | Yes | — | — | View |
| 20 |  TraceRoot | 6.5 | RecognisedAPIDocumented | $30/mo | Yes | — | 30 days | View |
| 21 | Amazon Bedrock Data AutomationAmazon Web Services | 6.5 | RecognisedAPIDocumented | — | — | — | — | View |
| 22 | Laminar | 6.4 | RecognisedAPIDocumented | $30/mo | Yes | 30 /mo | — | View |
| 23 |  Respan (formerly Keywords AI) | 6.2 | RecognisedAPIDocumented | — | Yes | 199 /mo | — | View |
| 24 | AgentOps | 6.1 | RecognisedAPIDocumented | — | Yes | 40 /mo | — | View |
| 25 | Fiddler AI | 6.0 | RecognisedAPIDocumented | — | Yes | — | — | View |
Is your platform on this list?
Numbered spots on this list can be sponsored. They are labelled, and the editorial order and scores never change for payment.
Questions about this list
Which ai agent observability tool is ranked first on Inferse?
Opik is ranked #1 of 30 with a score of 9.0. Langfuse is second and Arize AX third.
How many of these have a free plan?
15 of the 25 on this page publish a free plan on their own pricing pages.
Which is the cheapest paid option?
On this page, Opik has the lowest first paid tier we found: $19/mo.
How is this list ranked?
Ranked on what each maker publishes, open and connectable first: a public API, open-source code, the depth of its documentation and a free tier to try it on. Model lists are sorted by the figure in their title, exactly as each provider publishes it. Paid placements never change a rank.