Self-hosted LLM observability tools in 2026

Trace prompts, model calls and agent steps, and track cost, latency and output quality of AI applications. This list has 20 LLM observability tools. Of these, 11 are open source, 20 have a free plan and 20 can be self-hosted. Checked by hand on 30 September 2026.

  1. 1

    AgentOps

    Observability for AI agents: records agent sessions with LLM calls, tool use and costs so you can replay and debug runs; SDK and app are open source.

    Free plan Open source (MIT) Self-hosted LLM and AITraces
  2. 2

    Arize Phoenix

    Source-available LLM tracing and evaluation tool built on OpenTelemetry and OpenInference; run it locally, in a notebook or on your servers to inspect traces and score outputs.

    Free Self-hosted LLM and AITracesOpenTelemetry
  3. 3

    Braintrust

    Evaluation and observability platform for AI products: logs production traces, runs evals and scorers, and offers a prompt playground and datasets.

    Free plan Free: 1 GB processed data, 10k scores, 14-day retention Self-hosted LLM and AITraces
  4. 4

    Confident AI

    Evaluation and observability platform from the makers of the open source DeepEval library: LLM tracing, regression tests in CI, and red teaming.

    Free plan Free: 2 seats, 1 project, 1 GB-month of trace spans Self-hosted LLM and AITraces
  5. 5

    Future AGI

    Open source platform to trace, evaluate, simulate and guard LLM and agent apps, including an AI gateway.

    Free plan Open source (Apache-2.0) Self-hosted LLM and AITraces
  6. 6

    Galileo

    AI evaluation and observability platform with tracing, evaluation metrics and real-time guardrails for agents; hosted, VPC or on-prem.

    Free plan Self-hosted LLM and AITraces
  7. 7

    Helicone

    Open source LLM proxy and logging: point your provider base URL at it to record every request with cost, latency and user, plus caching and rate limits.

    Free plan Free: 10,000 requests, 1 GB storage, 1 seat Open source (Apache-2.0) Self-hosted maintenance LLM and AI
  8. 8

    HoneyHive

    Observability and evaluation platform for AI agents: OpenTelemetry-based tracing, automated and human evals, prompt versioning and production monitoring.

    Free plan Free: 10,000 events/mo, 5 users, 30-day retention Self-hosted LLM and AITracesOpenTelemetry
  9. 9

    Laminar

    Open source observability for AI agents: OpenTelemetry-based tracing, evaluations and analysis of agent runs, self-hostable or cloud.

    Free plan Free: 1 GB data, 7-day retention, 1 seat Open source (Apache-2.0) Self-hosted LLM and AITracesOpenTelemetry
  10. 10

    Langfuse

    Open source LLM engineering platform: traces LLM and agent calls, manages prompts, runs evaluations and tracks cost and latency. Self-host or use the cloud; acquired by ClickHouse in 2026.

    Free plan Free: 50k units/mo, 30 days data access, 2 users Open source (MIT) Self-hosted LLM and AITracesOpenTelemetry
  11. 11

    LangSmith

    LangChain's platform for tracing, evaluating and monitoring LLM apps and agents, usable with or without LangChain; also hosts agent deployments.

    Free plan Free: 5k base traces/mo, 1 seat Self-hosted LLM and AITraces
  12. 12

    LangWatch

    Open source LLMOps platform: traces LLM and agent runs, runs evaluations and agent simulations, and helps optimize prompts; cloud or self-managed.

    Free plan Free: 50k events/mo, 14-day data access, 2 users Open source (Apache-2.0) Self-hosted LLM and AITracesOpenTelemetry
  13. 13

    Latitude

    Open source platform to trace, monitor and evaluate AI agents in production, with prompt management; self-host or use the hosted plans.

    Free plan Free: 20K credits/mo, 30-day retention Open source (MIT) Self-hosted LLM and AITraces
  14. 14

    OpenLIT

    Open source, OpenTelemetry-native AI observability: SDK auto-instruments LLMs, vector databases and GPUs, with a self-hosted UI for traces, costs, evals and prompts.

    Free Open source (Apache-2.0) Self-hosted LLM and AITracesOpenTelemetry
  15. 15

    OpenLLMetry

    Open source OpenTelemetry instrumentations for LLM providers, vector databases and agent frameworks, by Traceloop; sends traces to any OTLP backend or the Traceloop platform.

    Free plan Free: Traceloop: 50K spans/mo, 5 seats, 24h retention Open source (Apache-2.0) Self-hosted LLM and AITracesOpenTelemetry
  16. 16

    Opik

    Open source LLM and agent observability from Comet: tracing, test suites, evaluations and a prompt optimizer; self-host the same code as the cloud.

    Free plan Free: 25k spans/mo, 10 members, 60-day retention Open source (Apache-2.0) Self-hosted LLM and AITraces
  17. 17

    Portkey

    AI gateway with an observability layer: one API for many model providers with routing, fallbacks and caching, and logs of each request with cost and latency. The gateway is open source.

    Free plan Free: 10k logs/mo, 3-day log retention Self-hosted LLM and AI
  18. 18

    PostHog

    Open source product suite with session replay, product analytics, feature flags, error tracking and LLM analytics sharing one event store. Hosted with a monthly free allowance, or self-hosted.

    Free plan Free: 5K session recordings and 1M events per month Open source (MIT) Self-hosted Session replayReal user monitoringErrors
  19. 19

    Respan

    LLM gateway, logging and evaluation platform (formerly Keywords AI): routes calls to many models through one API and records traces, cost and scores.

    Free plan Free: 100k logs, 1k scores Self-hosted LLM and AI
  20. 20

    W&B Weave

    Weights & Biases toolkit for tracing LLM calls, running evaluations with custom scorers and comparing model and prompt versions.

    Free plan Self-hosted LLM and AITraces

Side by side

Tool Pricing Free plan Open source Self-hosted LLM call tracingAgent and multi-step tracesToken and cost trackingPrompt managementEvaluationsDatasets and experimentsUser feedbackOpenTelemetry supportPlaygroundAlerts
AgentOps Free plan Yes Yes Yes YesYesYes----YesNo-
Arize Phoenix Free Yes No Yes YesYesYesYesYesYesYesYesYes-
Braintrust Free plan 1 GB processed data, 10k scores, 14-day retention No Yes YesYesYesYesYesYesYesYesYesYes
Confident AI Free plan 2 seats, 1 project, 1 GB-month of trace spans No Yes YesYesYesYesYesYesYesYes-Yes
Future AGI Free plan Yes Yes Yes YesYesYesYesYesYesYesYesYesYes
Galileo Free plan Yes No Yes YesYesYesYesYesYesYesYesYesYes
Helicone Free plan 10,000 requests, 1 GB storage, 1 seat Yes Yes YesYesYesYes-YesYesYesYesYes
HoneyHive Free plan 10,000 events/mo, 5 users, 30-day retention No Yes YesYesYesYesYesYesYesYesYesYes
Laminar Free plan 1 GB data, 7-day retention, 1 seat Yes Yes YesYesYes-YesYesYesYesYesYes
Langfuse Free plan 50k units/mo, 30 days data access, 2 users Yes Yes YesYesYesYesYesYesYesYesYes-
LangSmith Free plan 5k base traces/mo, 1 seat No Yes YesYesYesYesYesYesYesYesYesYes
LangWatch Free plan 50k events/mo, 14-day data access, 2 users Yes Yes YesYesYesYesYesYesYesYesYesYes
Latitude Free plan 20K credits/mo, 30-day retention Yes Yes YesYesYes-YesYesYesYes-Yes
OpenLIT Free Yes Yes Yes YesYesYesYesYes-YesYesYes-
OpenLLMetry Free plan Traceloop: 50K spans/mo, 5 seats, 24h retention Yes Yes YesYesYesYesYesYesYesYesYes-
Opik Free plan 25k spans/mo, 10 members, 60-day retention Yes Yes YesYesYesYesYesYesYesYesYesYes
Portkey Free plan 10k logs/mo, 3-day log retention No Yes YesYesYesYes--YesYesYesYes
PostHog Free plan 5K session recordings and 1M events per month Yes Yes YesYesYesYesYesYesYesYesYesYes
Respan Free plan 100k logs, 1k scores No Yes YesYesYes-YesYesYes--Yes
W&B Weave Free plan Yes No Yes YesYes-YesYesYesYesYesYesYes

Yes: confirmed in the tool's documentation. No: documented as not offered. -: not confirmed. Plans and prices change; check each tool's own site before you decide.

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