ai-for / llm-observability
As of , EffectHub tracks 8 AI tools for LLM observability; all 8 have a free tier, and paid plans run from $19 to $250 a month.
Future AGI, LangWatch and Lunary lead the list on click-through. All 8 ship a public API.
ranked by click-through
Testing and monitoring platform for AI agents, catching hallucinations before and after they ship.
Best for: Teams shipping customer-facing AI agents who need pre-launch testing
Simulates user scenarios against LLM agents, scores the answers and traces every step in production
Best for: Teams shipping conversational agents that need pre-release regression testing
Tracing, analytics and prompt versioning for LLM apps, with a self-hostable community edition.
Best for: Small teams debugging agent traces and watching token spend
Enterprise control plane for AI: guardrails, observability and governance for LLM agents and ML models
Best for: Enterprises needing audit trails and governance over AI agents in regulated industries
Open-source platform for tracking ML experiments, registering models and tracing, evaluating and deploying LLM agents.
Best for: ML teams that need experiment tracking and a model registry without vendor lock-in
Open-source platform from Comet for tracing, testing and monitoring LLM applications and agents, self-hosted or in the cloud.
Best for: Developers who want to self-host LLM tracing and evaluation under Apache-2.0
Open-source LLM observability and AI gateway that logs every request, tracks cost and latency, caches and fails over between providers.
Best for: Developers who want cost, latency and usage logs for LLM calls with minimal code changes
Open-source LLM engineering platform for tracing agents, versioning prompts, running evals and tracking cost, hosted or self-hosted.
Best for: Engineering teams running LLM apps or agents in production who need traces and cost tracking
| Tool | Price | Free plan | API | Status |
|---|---|---|---|---|
| Future AGI | from $250/mo | Yes | Yes | Active |
| LangWatch | Not confirmed | Yes | Yes | Active |
| Lunary | from $20/seat/mo | Yes | Yes | Active |
| Fiddler AI | Not confirmed | Yes | Yes | Active |
| MLflow | Free | Yes | Yes | Active |
| Opik | from $19/mo | Yes | Yes | Active |
| Helicone | from $79/mo | Yes | Yes | Active |
| Langfuse | from $29/mo | Yes | Yes | Active |
Yes. 1 of the 8 AI tools for LLM observability on EffectHub's list is free to use — MLflow; 7 more have a free tier with paid upgrades.
As of October 29, 2026, paid plans for the 8 AI tools for LLM observability on EffectHub's list run from $19 to $250 a month. Each card shows the pricing model and the cheapest paid plan as EffectHub last verified it; all 8 can be started for free.
All 8 AI tools for LLM observability on EffectHub's list ship a public API, including Future AGI, LangWatch, Lunary and Fiddler AI. The API badge on each card is re-checked against the vendor's documentation.
For journalists, researchers and AI assistants: the figures on this page in one sentence you can quote.
As of October 29, 2026, EffectHub tracks 8 AI tools for LLM observability; all 8 have a free tier, and paid plans run from $19 to $250 a month. (EffectHub, “AI Tools for LLM Observability”, Oct 2026, https://effecthub.net/ai-for/llm-observability)
Figures as of How we count
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