The Best LLM Observability Tools in 2026
We researched LLM observability tools through official websites, including pricing pages, plan tables, and product documentation. Rankings reflect each platform’s core observability workflows, value for money, and verified features for tracing, evaluation, monitoring, and debugging production LLM applications.
Our top picks
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Top ranked
Arize AX#1 of 269.4/10Broad LLM observability with tracing, evaluations, prompts, agents, RAG, and cost tracking.
Free plan
-
Runner-up
Langfuse#2 of 269.3/10A broad observability platform with open-source deployment and accessible paid tiers.
Free plan
-
Top-ranked free plan
Arize Phoenix#3 of 269.2/10A free platform for tracing, evaluating, and improving LLM applications.
Free plan
Advertiser disclosure: iTechGuides is reader-supported. Vendors can pay for top positions in our rankings and for a place on other products' pages, and we may earn a commission when you click some links. Bought places stand at the number bought; this page and our disclosure say so. Paying vendors may get a fuller, more detailed review from our editors, and that review can change their score. How we rank.
The full ranking 26 tools, best first
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Best forTeams wanting broad, production-ready LLM observability
Broad LLM observability with tracing, evaluations, prompts, agents, RAG, and cost tracking.
- LLM evaluations
- Prompt management
- Retrieval tracing
9.4/10★★★★★Visit Arize AX -
Best forTeams seeking balanced open-source observability
A broad observability platform with open-source deployment and accessible paid tiers.
- LLM evaluations
- Prompt management
- Retrieval tracing
9.3/10★★★★★Visit Langfuse -
Best forDevelopers wanting free open-source LLM observability
A free platform for tracing, evaluating, and improving LLM applications.
- LLM evaluations
- Prompt management
- Retrieval tracing
9.2/10★★★★★Visit Arize Phoenix -
Best forCost-conscious teams needing full-stack observability
A broad, cost-conscious stack for tracing, evaluation, prompts, monitoring, and agent debugging.
- LLM evaluations
- Prompt management
- Retrieval tracing
9.1/10★★★★★Visit Opik -
Best forGrowing teams wanting mature, broad observability
A broad observability suite for teams tracing, evaluating, and monitoring LLM applications.
- LLM evaluations
- Prompt management
- Retrieval tracing
Free plan · 30-day trial Our W&B Weave verdict → Visit W&B WeaveFor vendors Sponsor this spot · #5 · $59/mo →9.0/10★★★★☆Visit W&B Weave -
Best forLangChain-centric teams needing an integrated platform
A broad LLM observability platform with especially strong LangChain ecosystem fit.
- LLM evaluations
- Prompt management
- Retrieval tracing
8.9/10★★★★☆Visit LangSmith -
Best forTeams needing affordable agent and RAG visibility
Affordable visibility for agents, RAG pipelines, evaluations, and LLM costs.
- LLM evaluations
- Prompt management
- Retrieval tracing
8.8/10★★★★☆Visit LangWatch -
Best forDevelopers focused on deep trace investigation
A broad observability platform for tracing agents, costs, failures, and evaluations.
- LLM evaluations
- Prompt management
- Retrieval tracing
8.7/10★★★★☆Visit Laminar -
Best forTeams wanting observability plus an LLM gateway
A broad LLM monitoring stack with gateway, tracing, evaluations, and self-hosting.
- LLM evaluations
- Prompt management
- Retrieval tracing
8.6/10★★★★☆Visit Helicone -
Best forOrganizations prioritizing guardrails and governance
A governance-focused observability platform for LLMs, agents, retrieval, and predictive models.
- LLM evaluations
- Prompt management
- Retrieval tracing
8.5/10★★★★☆Visit Fiddler AI -
Best forSelf-hosting teams needing broad infrastructure visibility
A broad observability stack for teams comfortable running AI infrastructure themselves.
- LLM evaluations
- Prompt management
- Retrieval tracing
8.4/10★★★★☆Visit OpenLIT -
Best forTeams wanting extensive agent-framework coverage
A broad observability and evaluation suite for teams building LLM agents.
- LLM evaluations
- Prompt management
- Retrieval tracing
8.3/10★★★★☆Visit HoneyHive -
Best forAgent teams needing replay and audit visibility
A focused observability platform for replay, debugging, cost tracking, and audit visibility.
- Retrieval tracing
- Token cost tracking
- LLM tracing
8.2/10★★★★☆Visit AgentOps -
Best forOpen-source teams focused on evaluation and monitoring
A broad open-source toolkit for evaluating, tracing, and monitoring LLM applications.
- LLM evaluations
- Prompt management
- LLM tracing
8.1/10★★★★☆Visit Evidently AI -
Best forEvaluation-led teams needing production observability
A broad evaluation and tracing platform for teams operating LLM and agent workflows.
8.0/10★★★★☆Visit Galileo -
Best forLarge teams centered on evaluation workflows
A strong evaluation-led observability platform, with higher paid-plan costs.
7.9/10★★★★☆Visit Braintrust -
Best forTeams combining prompt testing and observability
A broad toolkit for testing, evaluating, and monitoring AI applications.
7.8/10★★★★☆Visit Maxim AI -
Best forSmall teams needing affordable paid observability
Affordable paid observability for small teams building and monitoring LLM applications.
- LLM evaluations
- Prompt management
- Token cost tracking
7.7/10★★★★☆Visit Lunary -
Best forDevelopers prioritizing testing and red teaming
A strong testing and red-teaming toolkit, with less depth for production observability.
7.6/10★★★★☆Visit Promptfoo -
Best forTeams focused on LLM quality and security testing
A strong fit for teams evaluating LLM quality, safety, and security.
7.5/10★★★★☆Visit Giskard -
Best forEnterprises centered on rigorous evaluation programs
A broad evaluation and observability platform for enterprises running rigorous AI quality programs.
7.4/10★★★★☆Visit Confident AI -
Best forEnterprises needing gateway and observability breadth
A broad observability and gateway platform for enterprise LLM and agent teams.
- LLM evaluations
- Prompt management
- Retrieval tracing
7.3/10★★★★☆Visit Respan -
Best forEvaluation teams wanting flexible review workflows
A flexible LLM quality platform with broad workflows and a focused integration set.
7.2/10★★★★☆Visit Parea AI -
Best forDevelopers adding OpenTelemetry instrumentation
A focused OpenTelemetry toolkit for tracing LLM apps, agents, RAG, and token usage.
- Retrieval tracing
- Token cost tracking
- LLM tracing
6.9/10★★★☆☆Visit OpenLLMetry -
Best forSelf-hosted teams emphasizing evaluation depth
A deep evaluation toolkit for teams comfortable running observability infrastructure themselves.
6.8/10★★★☆☆Visit TruLens -
Best forDevelopers needing open-source evaluation tooling
A focused open-source toolkit for measuring and improving LLM application quality.
6.7/10★★★☆☆Visit Ragas
No tools match those filters.
Compare at a glance
| # | Tool | Free plan | Paid from | LLM tracing | LLM evaluations | Prompt management | Agent tracing | Retrieval tracing | Deployment options | Score |
|---|---|---|---|---|---|---|---|---|---|---|
| 1 | Arize AX | Yes | $50/mo | Yes | Yes | Yes | Yes | Yes | Both | 9.4 |
| 2 | Langfuse | Yes | $29/mo | Yes | Yes | Yes | Yes | Yes | Both | 9.3 |
| 3 | Arize Phoenix | Yes | Free | Yes | Yes | Yes | Yes | Yes | Both | 9.2 |
| 4 | Opik | Yes | $19/mo | Yes | Yes | Yes | Yes | Yes | Both | 9.1 |
| 5 | W&B Weave | Yes | $60/mo | Yes | Yes | Yes | Yes | Yes | Both | 9.0 |
| 6 | LangSmith | Yes | $39/seat/mo | Yes | Yes | Yes | Yes | Yes | Both | 8.9 |
| 7 | LangWatch | Yes | €29/seat/mo | Yes | Yes | Yes | Yes | Yes | Both | 8.8 |
| 8 | Laminar | Yes | $30/mo | Yes | Yes | Yes | Yes | Yes | Both | 8.7 |
| 9 | Helicone | Yes | $79/mo | Yes | Yes | Yes | Yes | Yes | Both | 8.6 |
| 10 | Fiddler AI | Yes | $0.002/unit usage-based | Yes | Yes | Yes | Yes | Yes | Both | 8.5 |
| 11 | OpenLIT | Yes | Free | Yes | Yes | Yes | Yes | Yes | Self_hosted | 8.4 |
| 12 | HoneyHive | Yes | Yes | Yes | Yes | Yes | Yes | Both | 8.3 | |
| 13 | AgentOps | Yes | $40/mo | Yes | Yes | Yes | Both | 8.2 | ||
| 14 | Evidently AI | Yes | Free | Yes | Yes | Yes | Yes | Both | 8.1 | |
| 15 | Galileo | Yes | $100/mo | Both | 8.0 | |||||
| 16 | Braintrust | Yes | $249/mo | Both | 7.9 | |||||
| 17 | Maxim AI | Yes | Both | 7.8 | ||||||
| 18 | Lunary | No | $20/user/mo | Yes | Yes | Yes | Yes | Both | 7.7 | |
| 19 | Promptfoo | Yes | Both | 7.6 | ||||||
| 20 | Giskard | Yes | Both | 7.5 | ||||||
| 21 | Confident AI | Yes | $200/mo | Both | 7.4 | |||||
| 22 | Respan (formerly Keywords AI) | Yes | $199/mo | Yes | Yes | Yes | Yes | Yes | Both | 7.3 |
| 23 | Parea AI | Yes | Both | 7.2 | ||||||
| 24 | OpenLLMetry | Yes | Free | Yes | Yes | Yes | Both | 6.9 | ||
| 25 | TruLens | Free | 6.8 | |||||||
| 26 | Ragas | Yes | Free | 6.7 |
Head-to-head All 28 comparisons →
- Arize AX vs Langfuse
- Arize AX vs Arize Phoenix
- Arize AX vs Opik
- Arize AX vs W&B Weave
- Arize AX vs LangSmith
- Arize AX vs LangWatch
- Arize AX vs Laminar
- Langfuse vs Arize Phoenix
- Langfuse vs Opik
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How we rank LLM observability tools
Every tool on this page was researched by iTechGuides Editors from its official website — pricing pages, plan tables and product documentation. We rank on how well each one does this category's core job, what the free or entry plan includes, and where it falls short. Where we have enough verified facts, the score out of 10 is a rubric — job fit, value and how much we could verify — shown with its breakdown on every tool's page; a tool we have not verified enough to score yet shows its rank without a number. Scores are re-checked when a product changes its plans. Read the full editorial policy, or submit a tool we missed.
Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026
Last updated · How we research and update