Best LLM Observability Tools in 2026
Updated
In short: W&B Weave is ranked #1 of 26 as of 4 October 2026, ahead of Evidently AI and OpenLIT. The best-ranked option with a free plan is Evidently AI. The lowest first paid tier on this page is Respan (formerly Keywords AI) at $16.58/mo.
When you need visibility into LLM workflows, compare the kinds of activity each tool can trace and evaluate. Agent tracing, LLM tracing, and retrieval tracing describe different areas to examine; LLM evaluations and prompt management add other points of comparison. Token cost tracking, deployment options, free-plan availability, and paid-from pricing can help narrow the fit. The ranking begins with W&B Weave, Arize AX, and Langfuse, followed by Opik and OpenLIT. Arize Phoenix, Helicone, and LangSmith are also among the first entries. Consider which traces, evaluation features, and deployment choices align with your development work, using the listed criteria to compare the tools.
26 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 · 7.4 Free plan · $60/mo
#2 Evidently AI Runner-up · 7.3 Free plan · $80/mo
#3 OpenLIT Also great · 7.3 Free plan · Free- Free planFree trial apiLinuxmacOSself-hostedWebWindows
- Free plan
- Yes
- Paid from
- 60 /mo
- LLM tracing
- Yes
- LLM evaluations
- Yes
- Prompt management
- Yes
- Agent tracing
- Yes
RecognisedDocumentedFree planPlatforms$60/mofirst paid tier About W&B WeaveVisit site - Free planFree trial apiLinuxmacOSself-hostedWebWindows
- Free plan
- Yes
- LLM tracing
- Yes
- LLM evaluations
- Yes
- Prompt management
- Yes
- Agent tracing
- Yes
RecognisedDocumentedFree planPlatforms$80/mofirst paid tier About Evidently AIVisit site - Free plan apiLinuxmacOSself-hostedWebWindows
- Free plan
- Yes
- LLM tracing
- Yes
- LLM evaluations
- Yes
- Prompt management
- Yes
- Agent tracing
- Yes
RecognisedDocumentedFree planPlatforms - Free plan apiLinuxmacOSself-hostedWebWindows
- Free plan
- Yes
RecognisedDocumentedFree planPlatforms - Free planFree trial apiLinuxself-hostedWeb
- Free plan
- Yes
- Paid from
- 19 /mo
- LLM tracing
- Yes
- LLM evaluations
- Yes
- Prompt management
- Yes
- Agent tracing
- Yes
RecognisedDocumentedFree planPlatforms$19/mofirst paid tier About OpikVisit site - Free plan apiLinuxself-hostedWeb
- Free plan
- Yes
RecognisedDocumentedFree planPlatforms - Free plan apiself-hostedWeb
- Free plan
- Yes
- Paid from
- 29 /mo
- LLM tracing
- Yes
- LLM evaluations
- Yes
- Prompt management
- Yes
- Agent tracing
- Yes
RecognisedDocumentedFree planPlatforms$29/mofirst paid tier About LangfuseVisit site - Free plan apiself-hostedWeb
- Free plan
- Yes
- Paid from
- 50 /mo
- LLM tracing
- Yes
- LLM evaluations
- Yes
- Prompt management
- Yes
- Agent tracing
- Yes
RecognisedDocumentedFree planPlatforms$50/mofirst paid tier About Arize AXVisit site - Free plan apiself-hostedWeb
- Free plan
- Yes
- Paid from
- 200 /mo
RecognisedDocumentedFree planPlatforms$200/mofirst paid tier About Confident AIVisit site - Free plan apiself-hostedWeb
- Free plan
- Yes
- Paid from
- 100 /mo
RecognisedDocumentedFree planPlatforms$100/mofirst paid tier About GalileoVisit site - Free planFree trial apiself-hostedWeb
- Free plan
- Yes
- Paid from
- 79 /mo
- LLM tracing
- Yes
- LLM evaluations
- Yes
- Prompt management
- Yes
- Agent tracing
- Yes
RecognisedDocumentedFree planPlatforms$79/mofirst paid tier About HeliconeVisit site - Free plan apiself-hostedWeb
- Free plan
- Yes
- Paid from
- 30 /mo
- LLM tracing
- Yes
- LLM evaluations
- Yes
- Prompt management
- Yes
- Agent tracing
- Yes
RecognisedDocumentedFree planPlatforms$30/mofirst paid tier About LaminarVisit site - Free planFree trial apiself-hostedWeb
- Free plan
- Yes
RecognisedDocumentedFree planPlatforms$29/mofirst paid tier About Maxim AIVisit site - Free planFree trial apiself-hostedWeb
- Free plan
- Yes
- Paid from
- 199 /mo
- LLM tracing
- Yes
- LLM evaluations
- Yes
- Prompt management
- Yes
- Agent tracing
- Yes
RecognisedDocumentedFree planPlatforms$16.58/mofirst paid tier About Respan (formerly Keywords AI)Visit site - Free plan apiself-hostedWeb
- Free plan
- Yes
- Paid from
- 249 /mo
RecognisedDocumentedFree planPlatforms$249/mofirst paid tier About BraintrustVisit site - Free plan apiself-hostedWeb
- Free plan
- Yes
RecognisedDocumentedFree planPlatforms$150/mofirst paid tier About Parea AIVisit site - WebLinux
- Free plan
- Yes
- LLM tracing
- Yes
- LLM evaluations
- Yes
- Prompt management
- Yes
- Agent tracing
- Yes
RecognisedDocumentedFree planPlatforms - Web
- Free plan
- Yes
- Paid from
- 40 /mo
- LLM tracing
- Yes
- Agent tracing
- Yes
RecognisedDocumentedFree planPlatforms - Web
- Free plan
- Yes
- LLM tracing
- Yes
- LLM evaluations
- Yes
- Prompt management
- Yes
- Agent tracing
- Yes
RecognisedDocumentedFree planPlatforms - Web
- Free plan
- Yes
- LLM tracing
- Yes
- LLM evaluations
- Yes
- Prompt management
- Yes
- Agent tracing
- Yes
RecognisedDocumentedFree planPlatforms - Web
- Free plan
- Yes
- LLM tracing
- Yes
- LLM evaluations
- Yes
- Prompt management
- Yes
- Agent tracing
- Yes
RecognisedDocumentedFree planPlatforms - Web
- Free plan
- Yes
- LLM tracing
- Yes
- LLM evaluations
- Yes
- Prompt management
- Yes
- Agent tracing
- Yes
RecognisedDocumentedFree planPlatforms - Web
- Free plan
- No
- LLM tracing
- Yes
- LLM evaluations
- Yes
- Prompt management
- Yes
- Agent tracing
- Yes
RecognisedDocumentedFree planPlatforms -
- Free plan
- Yes
- LLM tracing
- Yes
- Agent tracing
- Yes
RecognisedDocumentedFree planPlatforms -
- Free plan
- Yes
RecognisedDocumentedFree planPlatforms
Is your app 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 LLM observability tool is ranked first on Everything Xiaomi?
W&B Weave is ranked #1 of 26 with a score of 7.4. Evidently AI is second and OpenLIT third.
How many of these have a free plan?
16 of the 25 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 what each maker publishes: documentation depth, a free tier and the platforms it runs on. Paid placements never change a rank.