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Patronus AI

Last updated June 16, 2026 · Reviewed by ToolForge Editorial

Eval and monitor your LLM apps in production.

★ 4.5/5 · 2K+ AI teams · Since 2023 · Free developer tier

What Patronus AI does best

Patronus AI is an evaluation and observability platform for LLM applications. Run automated evals, catch regressions, and monitor hallucination/PII leakage across every prompt you ship.

Who it's for: Eval and monitor your LLM apps in production.

Key features

Evals Automated scoring

Built-in + custom scorers for accuracy, faithfulness, tone, and more.

Monitoring Production traces

Log every LLM call, score it, alert on regressions.

PII scan Leak detection

Flags sensitive data leaving your prompts.

CI Regression gates

Block bad prompt changes in your pipeline before deploy.

The honest take

✓ What works

  • Best-in-class evals
  • Easy to self-host scorers
  • Strong free tier
  • Great docs

✗ What doesn't

  • Niche — for LLM builders only
  • Setup takes effort
  • Smaller than LangSmith
  • UI still maturing

Verdict

Patronus AI earns its place in a modern AI stack. Best-in-class evals — and at Free, it's an easy yes for the right use case.

💡 Transparency: This review contains affiliate links. If you sign up through our link, we may earn a commission at no cost to you. We only recommend tools we use ourselves. Full disclosure.

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