LLM Eval & Observabilityfree

DeepEval

Open-source LLM evaluation framework with pytest-style tests and 50+ metrics

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What DeepEval does

  • Open-source LLM evaluation framework with pytest-style tests and 50+ metrics
  • RAG, agent and conversational metrics; red-teaming module
  • Apache-2.0; optional Confident AI cloud has a free tier

DeepEval — straight answers

What is DeepEval?

DeepEval is listed under LLM Eval & Observability, in the AI Models & Local Execution category on Flocci AI Tools. Open-source LLM evaluation framework with pytest-style tests and 50+ metrics. It is free, with no paid plan attached, and it lives at github.com.

Is DeepEval free?

DeepEval 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 DeepEval in a browser, or is there an app?

DeepEval needs to be installed or self-hosted — it doesn't run in a browser tab. It is available on the command line and self-hosting.

What can DeepEval do?

DeepEval does 3 things the catalog singles out: Open-source llm evaluation framework with pytest-style tests and 50+ metrics; rag, agent and conversational metrics; red-teaming module; apache-2.0; optional confident ai cloud has a free tier.

What is the best free alternative to DeepEval?

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

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DeepEval alternatives

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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

DeepEval vs LangfuseDeepEval vs BraintrustDeepEval vs PromptfooDeepEval vs W&B WeaveDeepEval vs Arize PhoenixDeepEval vs Google Stax