Best AI LLM Observability Tools in 2026
Updated
In short: W&B Weave is ranked #1 of 23 as of 4 October 2026, ahead of Opik and Helicone. The best-ranked option with a free plan is Opik. The lowest first paid tier on this page is Respan (formerly Keywords AI) at $16.58/mo.
For teams building or operating applications that use large language models, observability tools can help track system behavior and review outputs. Opik, W&B Weave and Arize AX lead the ranking. Compare LLM trace capture, failure tracking and latency metrics, then consider output evaluations and token cost tracking for the signals you need to examine. Free-plan availability and retention may affect how you work with stored data, while paid starting price is another point to weigh. Langfuse, Helicone, Agenta, Maxim AI and Braintrust also appear near the start. The listed criteria can help you focus on tracing, evaluation, performance or cost monitoring.
23 AI LLM observability tools ranked on what their makers publish — plans and prices, free tiers, platforms and the facts on their own pages.
#1 W&B Weave Top pick · 8.0 Free plan · $60/mo
#2 Opik Runner-up · 7.8 Free plan · $19/mo
#3 Helicone Also great · 7.6 Free plan · $79/mo
- Free planFree trial apiLinuxmacOSself-hostedWebWindows
- Free plan
- Yes
- Paid from
- 60 /mo
- Token cost tracking
- Yes
RecognisedDocumentedFree planFree trialPlatforms$60/mofirst paid tier About W&B WeaveVisit site - Free planFree trial apiLinuxself-hostedWeb
- Free plan
- Yes
- Paid from
- 19 /mo
- Token cost tracking
- Yes
RecognisedDocumentedFree planFree trialPlatforms$19/mofirst paid tier About OpikVisit site - Free planFree trial apiself-hostedWeb
- Free plan
- Yes
- Paid from
- 79 /mo
- Token cost tracking
- Yes
RecognisedDocumentedFree planFree trialPlatforms$79/mofirst paid tier About HeliconeVisit site - Free planFree trial apiself-hostedWeb
- Free plan
- Yes
RecognisedDocumentedFree planFree trialPlatforms$29/mofirst paid tier About Maxim AIVisit site - Free planFree trial apiself-hostedWeb
- Free plan
- Yes
- Paid from
- 199 /mo
- Token cost tracking
- Yes
RecognisedDocumentedFree planFree trialPlatforms$16.58/mofirst paid tier About Respan (formerly Keywords AI)Visit site - Free plan apiLinuxmacOSself-hostedWebWindows
- Free plan
- Yes
- Token cost tracking
- Yes
RecognisedDocumentedFree planFree trialPlatforms - Free plan apiself-hostedWeb
- Free plan
- Yes
- Paid from
- 29 /mo
RecognisedDocumentedFree planFree trialPlatforms$29/mofirst paid tier About AgentaVisit site - Free plan apiself-hostedWeb
- Free plan
- Yes
- Paid from
- 49 /mo
- LLM trace capture
- Yes
- Token cost tracking
- Yes
- Output evaluations
- Yes
- Latency metrics
- Yes
RecognisedDocumentedFree planFree trialPlatforms$49/mofirst paid tier About PortkeyVisit site - Free plan apiself-hostedWeb
- Free plan
- Yes
- Paid from
- 100 /mo
RecognisedDocumentedFree planFree trialPlatforms$100/mofirst paid tier About GalileoVisit site - Free plan apiself-hostedWeb
- Free plan
- Yes
- Paid from
- 29 /mo
- Token cost tracking
- Yes
RecognisedDocumentedFree planFree trialPlatforms$29/mofirst paid tier About LangfuseVisit site - Free plan apiself-hostedWeb
- Free plan
- Yes
- Paid from
- 49 /mo
RecognisedDocumentedFree planFree trialPlatforms$49/mofirst paid tier About PromptLayerVisit site - Free plan apiself-hostedWeb
- Free plan
- Yes
- Paid from
- 50 /mo
- Token cost tracking
- Yes
RecognisedDocumentedFree planFree trialPlatforms$50/mofirst paid tier About Arize AXVisit site - Free plan apiself-hostedWeb
- Free plan
- Yes
- Paid from
- 249 /mo
RecognisedDocumentedFree planFree trialPlatforms$249/mofirst paid tier About BraintrustVisit site - Free plan apiself-hostedWeb
- Free plan
- Yes
- Token cost tracking
- Yes
RecognisedDocumentedFree planFree trialPlatforms - Free plan apiself-hostedWeb
- Free plan
- Yes
- Paid from
- 200 /mo
RecognisedDocumentedFree planFree trialPlatforms$200/mofirst paid tier About Confident AIVisit site - Web
- Free plan
- Yes
- Token cost tracking
- Yes
RecognisedDocumentedFree planFree trialPlatforms - Web
- Free plan
- Yes
- Token cost tracking
- Yes
RecognisedDocumentedFree planFree trialPlatforms - WebLinux
- Free plan
- Yes
- Token cost tracking
- Yes
RecognisedDocumentedFree planFree trialPlatforms - Web
- Free plan
- Yes
- Token cost tracking
- Yes
RecognisedDocumentedFree planFree trialPlatforms - Web
- Free plan
- Yes
- Token cost tracking
- Yes
RecognisedDocumentedFree planFree trialPlatforms -
- Free plan
- Yes
- Token cost tracking
- Yes
RecognisedDocumentedFree planFree trialPlatforms - Web
- Free plan
- No
- Token cost tracking
- Yes
RecognisedDocumentedFree planFree trialPlatforms - RecognisedDocumentedFree planFree trialPlatforms
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 LLM observability tool is ranked first on The Geeks Club?
W&B Weave is ranked #1 of 23 with a score of 8.0. Opik is second and Helicone third.
How many of these have a free plan?
15 of the 23 on this page publish a free plan on their own pricing pages.
Which is the cheapest paid option?
On this page, Respan (formerly Keywords AI) has the lowest first paid tier we found: $16.58/mo.
How is this list ranked?
Ranked on how quickly a newcomer can get going: documentation depth, a free tier or trial, and the platforms it runs on. Paid placements never change a rank.