The safety-first eval platform for production LLM apps

Patronus AI focuses on the things every LLM team worries about but few have time to measure: hallucinations, toxicity, PII leakage, and brand-safety regressions. Where Braintrust is eval-first, Patronus is safety-first — they ship out-of-the-box evaluators for the exact failure modes your legal team is asking about. Used by Notion, JetBlue, and Accenture.

Who it's for: AI teams in regulated industries (finance, healthcare, legal) or any team where hallucination risk is a board-level concern.

Key features

Hallucination detection Factual accuracy scoring

Detects when your model makes up facts. Pre-trained evaluators work out-of-the-box across domains.

Toxicity + PII Safety scanning

Catches toxic, biased, or PII-containing outputs. Compliance-grade reports for audits.

RAG evaluation Retrieval quality

Scores whether your RAG pipeline actually grounds answers in your source documents.

Online monitoring Production scoring

Score 100% of production traffic (not just samples). Surface drift + regressions in real time.

Evaluator SDK Build your own

Open-source Python SDK. Build custom evaluators. Run them in CI or in production.

The honest take

✓ What works

Out-of-the-box evaluators for the failure modes legal/compliance cares about
Used by named enterprises — credible for regulated industries
Open-source evaluator library is genuinely useful, even without the paid product
Strong RAG evaluation — most eval tools ignore retrieval quality
Online monitoring at scale — not just sampled eval

✗ What doesn't

Pricing is opaque — you'll need a sales call for anything beyond the free OSS library
More expensive than Braintrust for similar feature set
Smaller community than LangChain/LangSmith ecosystem
Less flexible than Braintrust for non-safety evals

Verdict

Patronus is the right pick if your AI feature is in a regulated industry or your biggest risk is hallucination/reputation damage. For pure AI engineering velocity, Braintrust is a better fit. For safety + compliance, Patronus pays for itself the first time it catches a PII leak before it hits prod.

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