AI observability AI tools

L

LangSmith

Free

AI observability

The end-to-end platform for building, testing, and monitoring LLM-powered applications

Free tier available · Paid plans for production use

A

AgentOps

Free

AI observability

Trace, Debug, & Deploy Reliable AI Agents — the leading developer platform for AI agents and LLM apps.

Free · Basic $0/mo · Pro $40+/mo · Enterprise custom

B

Braintrust

Free

AI observability

The AI observability platform for building quality AI products at scale

Flexible pricing plans for teams of all sizes

C

Cleanlab

Free

AI observability

Keep AI mistakes away from your customers.

C

Confident AI

Free

AI observability

Where AI Quality is Standardized. Not Improvised.

Free tier (limited to 2 seats, 1 project, 5 test runs/week, 1 GB-month traces). Starter at $200/month (unlimited seats, 5 projects, 5 GB-months traces then $1/GB-month). Team at $2,000/month (unlimited seats and projects, 75 GB-months then $1/GB-month). Enterprise at custom pricing (unlimited everything, on-prem, HIPAA, etc.).

H

HoneyHive

Free

AI observability

Agent Observability and Evaluation Platform

Free tier includes 10,000 events/month, up to 5 users, 30-day data retention, automated & human evaluations, prompt versioning, CI/CD integration, and community support. Enterprise tier offers custom usage limits, unlimited users & workspaces, SAML & custom SSO, custom data retention, uptime SLA, custom DPA and BAA, dedicated TAM & QBRs, and optional self-hosting/hybrid/single-tenant deployment.

L

Langfuse

Free

AI observability

Open-source AI engineering platform to debug, monitor, and improve LLM applications and agents

Hobby (free): 50k units/month, 30 days data access, 2 users. Core: $29/month, 100k units/month included, 90 days data access, unlimited users. Pro: $199/month, 100k units/month included, 3 years data access, high rate limits, SOC2 & ISO27001. Enterprise: $2,499/month. Additional usage: $8/100k units.

L

Lunary

AI observability

Build AI agents with confidence

Team plan at $20/user/month (50,000 events/month included, 300 AI Playground queries/month, unlimited projects, 1 year history). Usage above included allowance billed separately ($10/50k events/month). Enterprise plan is custom-priced.

M

MLflow

Free

AI observability

The leading open source AI engineering platform for Agents, LLMs & Models

100% open source under Apache 2.0 license. Forever free, no strings attached.

O

Opik

Free

AI observability

Open-source AI observability & evaluation platform for the agentic era

Free tier available, enterprise versions for teams

P

Patronus AI

Free

AI observability

Simulating the World's Intelligence

Free Developer tier (no credit card required, 2 projects, 5 experiments/project, 2-week data access, $10 free API credits). API usage: $10/1k small evaluator calls, $20/1k large evaluator calls, $10/1k eval explanations. Enterprise: contact for pricing, unlimited everything, on-prem/VPC, SSO, custom data retention.

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Phoenix

Free

AI observability

The open-source platform for AI agent development, tracing, and evaluation

Free OSS with paid Cloud instances available

P

PromptLayer

Free

AI observability

The collaboration layer for AI engineering teams — prompt CMS, eval harness, and observability stack

T

Traceloop

Free

AI observability

LLM reliability platform that turns evals and monitors into a continuous feedback loop

Free tier available · enterprise plans