AI Tools
Best AI LLM Observability Tools in 2026
For software built around large language models, observability can help you inspect requests, failures, output quality, performance, and token use. Compared on LLM trace capture, failure tracking, latency metrics, output evaluations, and token cost tracking, these tools also specify free-plan availability, retention, and paid starting prices.
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Agenta Agenta suits teams that want to create, automate, and monitor AI agents across connected tools.
From $29/mo Free plan Open source Web · API · Self-hosted9.3 Visit Specs - 02
Braintrust Braintrust is aimed at teams operating AI agents in production, from early-stage teams to enterprises.
From $249/mo Free plan Web · API · Self-hosted9.2 Visit Specs - 03
LangSmith LangSmith suits teams engineering AI agents that need evaluation, tracing, prompt work, deployment, and production monitoring.
From $39/mo Free plan Web · Windows · macOS · Linux9.1 Visit Specs - 04
LangWatch LangWatch suits AI teams shipping agents, including developers, product owners, QA, and domain experts working with evaluation workflows.
From €29/mo Free plan Open source Web · macOS · Linux · API9.1 Visit Specs - 05
Langfuse Langfuse suits teams building AI agent applications that need tracing, prompt management, and evaluation tools.
From $29/mo Free plan Open source Web · Linux · API · Self-hosted9.0 Visit Specs - 06
Opik Opik suits teams developing applications or agents that make calls to an LLM and want tracing and evaluation across the development cycle.
From $19/mo Free plan Open source Web · Windows · macOS · Linux8.8 Visit Specs - 07
W&B Weave Weave suits teams monitoring and evaluating production AI agents, particularly those using supported frameworks and models.
From $60/mo Free plan Open source Web · Windows · macOS · Linux8.6 Visit Specs - 08 OpenLIT
OpenLIT suits teams that need LLM tracing, evaluation, prompt management, and cost tracking, especially those seeking self-hosted deployment.
Free plan Open source Web · Windows · macOS · Linux8.5 Visit Specs - 09 Arize AX
AX suits teams building AI agents that need tracing, evaluations, investigations, and experiments.
From $50/mo Free plan Web · API · Self-hosted8.4 Visit Specs - 10
Confident AI It suits engineers, QA teams, product managers, subject-matter experts, and annotators responsible for AI quality and governance.
From $200/mo Free plan Web · API · Self-hosted8.4 Visit Specs - 11 MLflow Tracing Free plan Open source Web · Linux · API · Self-hosted8.4 Visit Specs
- 12 Lunary From $20/mo Open source Web · API · Self-hosted8.3 Visit Specs
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Helicone Helicone suits teams routing and observing AI application requests across model providers, including teams that need self-hosting or LLM cost tracking.
From $79/mo Free plan Web · API · Self-hosted8.2 Visit Specs - 14 Arize Phoenix
It suits teams operating AI applications that need model, retrieval, tool, prompt, and evaluation tracing.
Free plan Web · API · Self-hosted8.1 Visit Specs - 15
Maxim AI It suits cross-functional AI teams that need to evaluate agents and monitor them in production.
From $29/mo Free plan Web · API · Self-hosted8.1 Visit Specs - 16
Fiddler AI Fiddler positions its platform for enterprises managing AI agents and predictive applications at scale.
Free plan Web · API · Self-hosted8.0 Visit Specs - 17 Portkey
Portkey suits teams that need a common API and operational controls for generative AI models and providers.
From $49/mo Free plan Web · API · Self-hosted8.0 Visit Specs - 18
Galileo Galileo is designed for engineers, product managers and subject matter experts building AI applications.
From $100/mo Web · API · Self-hosted7.9 Visit Specs - 19 TruLens Free plan Open source API · Self-hosted7.9 Visit Specs
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HoneyHive HoneyHive is aimed at AI platform teams, AI engineers, domain experts, and risk or governance teams.
Free plan Web · API · Self-hosted7.8 Visit Specs - 21
PromptLayer PromptLayer is for engineers and domain experts who build or improve AI products together.
From $49/mo Free plan Web · API · Self-hosted7.7 Visit Specs - 22 Respan (formerly Keywords AI)
Respan suits teams that need to route model requests while tracing and evaluating AI workflows in production.
From $16.58/mo Free plan Web · API · Self-hosted7.7 Visit Specs - 23 OpenLLMetry Web · API · Self-hosted6.9 Visit Specs
W&B Weave, Opik, and OpenLIT are among the options to consider. Think about which signals you need to follow in your own workflow, whether you need to evaluate outputs or diagnose failures, and how much visibility into latency and token costs is useful.