Ship AI apps with the same confidence as traditional software

Composo is an API that gives you deterministic evals for shipping high reliability LLM agents & features.

You've hit the limits of testing by vibes.

You need evals that give you 100% confidence when shipping LLM agents & features. LLM-as-judge gives you vibes, not reliable testing. Manual reviews can't keep pace.

We've built deterministic evaluation models you can rely on

Our proprietary generative reward models are specifically trained for evaluation - not just LLM as a Judge. Get deterministic precision, focused measurement, and results you can stake your product on.

Test & iterate faster in development

Instant feedback on every change. Debug in minutes, not days. Track quality over time with scores that don't jump around.

Have 100% confidence when you ship

Finally get metrics you can show stakeholders. Know exactly what's not working before it gets to production.

Rapidly find & fix edge cases in production

Understand what real-world users like and dislike, and what changes you need to make as a result.

Why companies choose Composo

5 mins to set up

Simple API integration with single-sentence criteria. No complex prompt engineering or optimization needed.

Enterprise-ready from day one

Built for enterprise-scale teams, with robust compliance and secure integration into your stack.

Results you can trust

Deterministic 0-1 scores with clear explanations. Same input = same score, every time.

Built for complex agents

Handles tool calling, retrieval & multi-step reasoning.

Industry leading research

92% accuracy vs 72% for LLM judges. Proven on real-world enterprise use cases.

Fully customisable

Single-sentence custom criteria for any domain. Medical, legal, financial - we handle complexity.

We're trusted by the best teams in AI

Proven results across startups & enterprises in the most complex verticals

"We were finding LLM as a Judge far too unreliable - the same response would score 40% one day and 70% the next. Composo gave us the deterministic scoring we needed to actually track improvements. Game changer for our ML team."

Senior ML Engineer

Fortune 500 Financial Services

"This is awesome. We replaced our entire LLM-as-judge system in one afternoon. We just run all our outputs through Composo and get super powerful metrics on performance. Why would anyone do it the old way?"

CTO

Series B Healthcare AI Startup

"Our enterprise clients demand quantitative proof that our AI agents are accurate. Composo's 92% accuracy finally gave us the hard metrics we needed to prove our system delivers on its promises."

VP of Product

Legal Tech Company

"We cut our QA cycle time by 70%. Instead of relying purely on human review, now we instantly know which prompts are failing and why. The detailed analysis helps us fix issues before they hit production."

Head of AI Engineering

Enterprise SaaS platform