18.7
W&B Weave provides observability and continuous improvement tools for production AI agents.
Free planOpen sourceiOSWebAPI
Best AI LLM Observability Tools in 2026
For software built around large language models, observability can help you inspect requests, identify failures and assess outputs and costs. Compared on LLM trace capture, failure tracking, latency metrics, output evaluations and token cost tracking, these tools provide criteria for deciding which signals matter to your work. Free-plan access and retention can affect how much history you can review, while paid-from…
28.4
Opik helps teams building applications or agents that call an LLM log actions and evaluate behavior through development, testing, and production.
Free planOpen sourceWebAPILinux
38.2
Langfuse is an open-source AI engineering platform for teams debugging, analyzing, and iterating on AI agent applications.
Free planOpen sourceWebAPILinux
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LangWatch
LangWatch is an AI agent engineering platform for teams preparing agents for production.
Free planOpen sourceWebAPILinuxmacOS8.2From €29 a month - 5
Agenta
Agenta is an open-source workspace for teams to build, use, and automate AI coworkers.
Free planOpen sourceWebAPISelf-hosted8.0From $29 a month - 6
LangSmith
LangSmith is a platform for building, evaluating, deploying, monitoring, and improving AI agents.
Free planWebAPILinuxmacOS8.0$39 usage-based - 7
Braintrust
Braintrust is an observability platform for teams improving AI agents that run in production.
Free planWebAPISelf-hosted7.7From $249 a month - 8
OpenLIT
OpenLIT is an open-source Agent Harness Engineering platform for LLM tracing, evaluations, prompt management and cost tracking, built on OpenTelemetry.
Free planOpen sourceWebAPILinuxmacOS7.7Free plan - 9
MLflow Tracing
MLflow Tracing records inputs, outputs and metadata from steps in LLM application and agent requests, helping teams investigate bugs and unexpected behavior.
Free planOpen sourceWebAPILinuxSelf-hosted7.2Free plan - 10
TruLens
TruLens is a free, open-source Python SDK for tracing and evaluating AI agents, RAG applications, MCP apps, and summarization systems.
Free planOpen sourceAPISelf-hosted7.2Free plan - 11
Lunary
Lunary is an AI platform for enterprises and developers building chatbots or other applications powered by large language models.
Open sourceWebAPISelf-hosted7.1From $20 a month - 12
Maxim AI
Maxim AI is an evaluation and observability platform for simulating, assessing, and monitoring AI agents.
Free planWebAPISelf-hosted7.0From $29 a month - 13
PromptLayer
PromptLayer is a platform for teams that build and improve AI products.
Free planWebAPISelf-hosted7.0From $49 a month - 14
Confident AI
Confident AI is an AI quality platform for evaluating application changes during development and monitoring AI applications in production.
Free planWebAPISelf-hosted6.9From $200 a month - 15
Galileo
Galileo is an observability, evaluation, and guardrail platform for generative AI and agentic applications.
Free planWebAPISelf-hosted6.9From $100 a month - 16
Helicone
Helicone is a platform for routing, debugging, and analyzing AI applications.
Free planWebAPISelf-hosted6.9From $79 a month - 17
Arize AX
Arize AX is a platform for improving AI agents by turning production behavior into issues, investigations, evaluations, and experiments.
Free planWebAPISelf-hosted6.8From $50 a month - 18
Portkey
Portkey is a platform for managing, observing, and governing generative AI across teams.
Free planWebAPISelf-hosted6.8From $49 a month - 19
Respan (formerly Keywords AI)
Respan (formerly Keywords AI) is an AI gateway with tools for observing, evaluating, and security testing AI systems.
Free planWebAPISelf-hosted6.7From $199 a year - 20
Fiddler AI
Free planWebAPISelf-hosted6.4Free plan - 21
HoneyHive
HoneyHive is an agent observability platform for teams that want to observe, evaluate, and improve AI agents in production.
Free planWebAPISelf-hosted6.4Free plan - 22
Arize Phoenix
Arize Phoenix helps teams trace, evaluate, debug, and improve AI applications.
Free planWebAPISelf-hosted6.3Free plan - 23
OpenLLMetry
OpenLLMetry is free, Apache-2.0 software for monitoring and debugging LLM application execution.
Free planWebAPISelf-hosted6.1Free plan