LLM Eval & Observabilityfree

Laminar

Open-source observability and evals platform for AI agents (Apache-2.0)

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What Laminar does

  • Open-source observability and evals platform for AI agents (Apache-2.0)
  • Traces, session replay for browser agents and evaluations
  • Self-hostable

Laminar — straight answers

What is Laminar?

Laminar is listed under LLM Eval & Observability, in the AI Models & Local Execution category on Flocci AI Tools. Open-source observability and evals platform for AI agents (Apache-2.0). It is free, with no paid plan attached, and it lives at github.com.

Is Laminar free?

Laminar is listed as fully free — there is no paid tier attached to it in the catalog. That makes it one of the 397 entries on Flocci AI Tools with no upgrade path built in.

Can I use Laminar in a browser, or is there an app?

Laminar works in a normal browser tab with no install. It is available on the web, self-hosting and an API.

What can Laminar do?

Laminar does 3 things the catalog singles out: Open-source observability and evals platform for ai agents (apache-2.0); traces, session replay for browser agents and evaluations; self-hostable.

What is the best free alternative to Laminar?

Arize Phoenix is the closest free alternative: it sits in the same LLM Eval & Observability sub-category and is free. Google Stax, DeepEval and EleutherAI LM Evaluation Harness also start free. The full list is on the alternatives page.

See the full list →

Laminar alternatives

Compare all alternatives →

Langfuse

LLM Eval & Observability
freemium
  • Fully open-source and self-hostable for free via Docker Compose/Kubernetes, not just a hosted SaaS
  • Hobby cloud plan is free with no credit card, 50k observability units/month
  • Combines tracing, prompt management, evals and datasets in one open platform
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Braintrust

LLM Eval & Observability
freemium
  • Free Starter plan ships model credits and scored evals with no card required
  • Unlimited users/projects/datasets/playgrounds even on the free tier
  • Built-in playground for side-by-side prompt/model comparison against production traces
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Promptfoo

LLM Eval & Observability
freemium
  • Open-source CLI/library for evaluating prompts, models and RAG pipelines side by side, runs in CI
  • Automated red-teaming to surface prompt injection, jailbreak and data-leak vulnerabilities
  • 300,000+ user community with an enterprise tier for teams needing hosted guardrails
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W&B Weave

LLM Eval & Observability
freemium
  • Agent-native tracing model with sessions, steps, tools and sub-agents as first-class concepts (not generic spans)
  • Pre-built safety/quality scorers for toxicity, bias, PII and hallucination detection out of the box
  • Built on Weights & Biases' existing ML-experiment infrastructure, useful for teams already on W&B
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Arize Phoenix

LLM Eval & Observability
free
  • Fully open-source, self-hostable with zero setup via `uvx` (pip/conda also supported)
  • Combines tracing, evals, datasets, experiments and prompt playground in one local-first tool
  • AI engineering agent (PXI) built in for automated troubleshooting of traces
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Google Stax

LLM Eval & Observability
free
  • Build evals with human raters or LLM autoraters on your own data
  • Compare models and prompts on quality, latency and token cost
  • Prebuilt and custom evaluators
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Head-to-head comparisons

Laminar vs LangfuseLaminar vs BraintrustLaminar vs PromptfooLaminar vs W&B WeaveLaminar vs Arize PhoenixLaminar vs Google Stax