Weave suits teams building or operating production AI agents that need tracing, evaluations, interaction monitoring, or prompt comparisons.
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Best LLM Observability Tools 2026
Facts read 29 Sep 2026 – 21 Oct 2026
When you need visibility into how language-model applications behave, compare what each tool can trace and evaluate. Compared on agent tracing, LLM tracing, and retrieval tracing, these entries also cover LLM evaluations, prompt management, and token cost tracking. Deployment options, free-plan availability, and paid-from pricing can help you assess operational fit and cost. Arize AX, Evidently AI, and Helicone are among the named options, alongside Laminar, Langfuse, OpenLIT, Opik, and Respan (formerly Keywords AI). Consider which signals matter in your workflows, how you want to deploy a tool, and whether its listed evaluation and prompt features suit the way you build and oversee LLM-powered software.
The standings: top 10
| Name | In a line | Record score | Price from | Try it free | Runs on | Facts read |
|---|---|---|---|---|---|---|
| 01 W&B Weave | Weave suits teams building or operating production AI agents that need tracing, evaluations, interaction monitoring, or prompt comparisons. | 6.2 | $60 a month | Free plan | iPhone & iPad, Web, Windows, Mac | 20 Oct 2026 |
| 02 Evidently AI | Evidently AI suits teams evaluating or monitoring language models, RAG applications, agents, or predictive ML workflows. | 6.1 | $80 a month | Free plan | Web, Windows, Mac, Linux | 15 Oct 2026 |
| 03 Opik | Opik suits teams developing applications or agents that call an LLM and need to inspect, evaluate, and monitor their behavior. | 6.1 | $19 a month | Free plan | Web, Windows, Mac, Linux | 21 Oct 2026 |
| 04 Langfuse | Langfuse suits teams building AI agent applications that need tracing, prompt management, and evaluation tools. | 5.7 | $29 a month | Free plan | Web, Linux, API, Self-hosted | 15 Oct 2026 |
| 05 LangWatch | LangWatch suits AI teams working on agents, including developers, product owners, QA, and domain experts involved in evaluation workflows. | 5.7 | €29 a month | Free plan | Web, Mac, Linux, API | 21 Oct 2026 |
| 06 OpenLIT | OpenLIT suits developers who want to observe LLM applications, prompts, evaluations, and costs. | 5.5 | Free plan | Free plan | Web, Windows, Mac, Linux | 14 Oct 2026 |
| 07 LangSmith | LangSmith suits teams developing AI agents that need evaluation, prompt tools, tracing, and production monitoring. | 5.3 | $39 usage-based | Free plan | Web, Windows, Mac, Linux | 15 Oct 2026 |
| 08 Promptfoo | Promptfoo is for developers and enterprises building AI applications who need prompt evaluation or red-team testing. | 5.3 | Free plan | Free plan | Web, Windows, Mac, Linux | 15 Oct 2026 |
| 09 Giskard | It suits teams assessing conversational AI agents for safety and quality issues before production. | 5.2 | Free plan | Free plan | Web, Linux, API, Self-hosted | 21 Oct 2026 |
| 10 Maxim AI | It is designed for cross-functional AI teams, including product managers who want to define and analyze evaluations without code and developers who use SDKs, a CLI, or… | 5.2 | $29 a month | Free plan | Web, API, Self-hosted | 2 Oct 2026 |
02
Evidently AI
Evidently AI suits teams evaluating or monitoring language models, RAG applications, agents, or predictive ML workflows.
WebWindowsMac+3 Record6.1 Visit
03
Opik
Opik suits teams developing applications or agents that call an LLM and need to inspect, evaluate, and monitor their behavior.
WebWindowsMac+3 Record6.1 Visit
04
Langfuse
Langfuse suits teams building AI agent applications that need tracing, prompt management, and evaluation tools.
WebLinuxAPI+1 Record5.7 Visit
05
LangWatch
LangWatch suits AI teams working on agents, including developers, product owners, QA, and domain experts involved in evaluation workflows.
WebMacLinux+2 Record5.7 Visit
6
OpenLIT
WebWindowsMac+3 Free plan Record5.5 Visit OpenLIT suits developers who want to observe LLM applications, prompts, evaluations, and costs.
7
LangSmith
WebWindowsMac+3 $39 usage-based Record5.3 Visit LangSmith suits teams developing AI agents that need evaluation, prompt tools, tracing, and production monitoring.
8
Promptfoo
WebWindowsMac+3 Free plan Record5.3 Visit Promptfoo is for developers and enterprises building AI applications who need prompt evaluation or red-team testing.
9
Giskard
WebLinuxAPI+1 Free plan Record5.2 Visit It suits teams assessing conversational AI agents for safety and quality issues before production.
10
Maxim AI
WebAPISelf-hosted $29 a month Record5.2 Visit It is designed for cross-functional AI teams, including product managers who want to define and analyze evaluations without code and developers who use SDKs, a CLI, or…
12
Braintrust
WebAPISelf-hosted $249 a month Record5.0 Visit Braintrust is intended for teams running AI agents in production, from early-stage projects to enterprise deployments.
13
Helicone
WebAPISelf-hosted $79 usage-based Record5.0 Visit It suits teams building or operating AI applications that need provider routing, request tracing, or cost visibility.
14
Confident AI
WebAPISelf-hosted $200 a month Record4.8 Visit It is designed for engineers, QA teams, product managers, subject-matter experts, and annotators working on AI quality, evaluation, or production monitoring.
16
Respan (formerly Keywords AI)
WebAPISelf-hosted $199 a year Record4.8 Visit Respan suits startup and enterprise teams tracing workflows, evaluating agent behavior, and monitoring production AI systems.
18
Fiddler AI
WebAPISelf-hosted Free plan Record4.7 Visit Fiddler AI is aimed at enterprises managing AI agents and predictive applications at scale, including teams that need monitoring, guardrails, and audit evidence.
19
Laminar
WebAPISelf-hosted $30 a month Record4.7 Visit Laminar suits teams building AI agents that need to trace model and tool activity, investigate runs, or evaluate changes against datasets.
20
Arize AX
WebAPISelf-hosted $50 a month Record4.4 Visit Arize AX suits teams working to observe, evaluate, and improve AI agents in production.
21
Galileo
WebAPISelf-hosted $100 a month, billed yearly Record4.4 Visit Galileo is designed for engineers, product managers, and subject matter experts building AI applications.
22
HoneyHive
WebAPISelf-hosted Free plan Record4.4 Visit It suits AI platform teams, AI engineers, domain experts, and risk and governance teams that need production agent visibility.
23
Parea AI
WebAPISelf-hosted $150 a month Record4.4 Visit Parea suits teams developing LLM applications that need evaluation, production observability, and human review.
24
Arize Phoenix
WebAPISelf-hosted Free plan Record4.3 Visit Phoenix suits teams that need to inspect AI application traces and compare evaluation results across versions.
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