PromptEval

PromptEval is an AI prompt evaluation and optimization platform built for developers, AI engineers, and teams shipping LLM-powered products.

What it does Paste any prompt and receive a structured score from 0 to 100 across four dimensions: clarity, specificity, structure, and goal alignment. Each dimension includes a detailed explanation of what is weak and why it affects model output — not just a number. Pro users also get an AI-generated improved version of their prompt with a side-by-side diff.

Full feature set

• Prompt Evaluator: score any prompt in seconds, no API key needed
• Prompt Library: save prompts with unlimited version history, tags, and use-case metadata
• Production Iterator: make surgical edits to prompts already in production without breaking what works
• A/B Testing Wizard: compare two prompt variants across a real test set with an LLM judge
• Playground: test prompt outputs across different models side by side
• Daily Challenge: a new prompt engineering challenge every day with a public leaderboard
• Token Counter: free tool to count tokens across OpenAI, Anthropic, and Google models
• REST API (Team): integrate prompt evaluation directly into CI/CD pipelines — fail builds when prompt quality drops
• Slug API (Team): serve versioned prompts from the library directly into production code without redeployment

Who it's for Developers who write system prompts and need to validate quality before deploying. AI engineers running prompt iteration cycles. Teams that want a version-controlled prompt library instead of scattered docs and Notion pages.

Pricing Free — 3 evaluations/month, up to 5 saved prompts Pro — $19/month, unlimited evaluations and library Team — $49/month, Pro + REST API + slug API for production prompt serving

No credit card required to start. Works with prompts for any LLM — GPT, Claude, Gemini, Llama, and others.