Best LLM Observability Tools

Compare 4 top-rated llm observability tools. Find features, pricing, pros, cons, and alternatives.

🏆 Top Tools in This Category

AIMon

🔴Developer

AIMon (officially AIMon Labs) is a Bessemer Venture Partners-backed LLM evaluation and monitoring product focused on the hard problems that show up the moment an AI app reaches real users: hallucinations, instruction-following drift, completeness gaps, conciseness regressions, and toxicity or PII leakage. The team's bet is that generic LLM-as-judge approaches...

Braintrust

MCP
MCP Client
🔴Developer

AI observability platform for evals, production tracing, prompt management, and regression detection.

Starter is $0/month with 1 GB processed data, 10k scores and 14-day retention, then $4/GB and $2.50 per 1k scores. Pro is $249/month with 5 GB processed data, 50k scores and 30-day retention, then $3/GB and $1 per 1k scores. Enterprise is custom with RBAC, premium support, custom retention/export, and on-prem or hosted deployment options.View Details →

Helicone

🔴Developer

Open-source LLM observability and AI gateway — logs every prompt, response, cost, and latency across 20+ providers with a one-line proxy or async SDK, plus caching, retries, and prompt experiments.

Langfuse

🔴Developer

Langfuse is an open-source LLM observability and engineering platform providing tracing, prompt management, evaluations, and dataset management for production AI applications.

Free tier + Cloud plans from $29/monthView Details →

LLM Observability tools

AIMon

🔴Developer

AIMon (officially AIMon Labs) is a Bessemer Venture Partners-backed LLM evaluation and monitoring product focused on the hard problems that show up the moment an AI app reaches real users: hallucinations, instruction-following drift, completeness gaps, conciseness regressions, and toxicity or PII leakage. The team's bet is that generic LLM-as-judge approaches are too slow and too expensive for production guardrails — so AIMon ships fine-tuned small-model detectors (the HDM-2 family of hallucinat

Key Features:

    Freemium

    Braintrust

    MCP
    MCP Client
    🔴Developer

    AI observability platform for evals, production tracing, prompt management, and regression detection.

    Key Features:

    • Workflow Runtime
    • Tool and API Connectivity
    • State and Context Handling

    Starter is $0/month with 1 GB processed data, 10k scores and 14-day retention, then $4/GB and $2.50 per 1k scores. Pro is $249/month with 5 GB processed data, 50k scores and 30-day retention, then $3/GB and $1 per 1k scores. Enterprise is custom with RBAC, premium support, custom retention/export, and on-prem or hosted deployment options.

    Helicone

    🔴Developer

    Open-source LLM observability and AI gateway — logs every prompt, response, cost, and latency across 20+ providers with a one-line proxy or async SDK, plus caching, retries, and prompt experiments.

    Key Features:

    • Proxy-Based Request Logging
    • Cost Analytics & Budget Alerts
    • Gateway-Level Caching

    Paid

    🏆 Best Enterprise Value

    Langfuse

    🔴Developer

    Langfuse is an open-source LLM observability and engineering platform providing tracing, prompt management, evaluations, and dataset management for production AI applications.

    Key Features:

    • Hierarchical Tracing & Agent Debugging
    • Production Prompt Management & Versioning
    • LLM-as-Judge Evaluation Framework

    Free tier + Cloud plans from $29/month

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