PromptEval vs PromptPerfect

PromptEval is a web and API SaaS platform for evaluating and optimizing large-language-model prompts. It assigns a reproducible score from 0 to 100, with diagnostics covering clarity, specificity, structure and robustness, then identifies issues, warnings, strengths and targeted fixes. A token optimizer compresses prompts while preserving intent and reports the reduction percentage. Its versioned library keeps prompt history, score changes and diffs. The A/B Playground compares two prompts across as many as seven criteria using a user-provided API key. An official GitHub Action can fail pull requests after score drops, contradictions or production regressions. Pro and Team users can serve prompts by slug through an API endpoint, with changes taking effect in about 60 seconds. Plans include a free tier, Basic at $9 a month, Pro at $19 a month, and custom-priced Team.

PromptPerfect is an open-source prompt optimizer from Beagle, available as a web app, Chrome extension, and API. In the web app, users submit a draft, choose an optimization mode, and receive rewritten text with an explanation of the changes. Modes include better, specific, cot, developer, research, beginner, product, and marketing. The Chrome extension is described as working on sites including ChatGPT and Gmail. Its API accepts a draft prompt and returns optimized text, an explanation, changes, the original text, provider, and model. Gemini, OpenAI, and Anthropic providers are supported. API keys can be supplied in the request body or as a Bearer token, with the Bearer token taking precedence. The homepage says keys stay in the browser and the project uses the MIT License. The Free plan costs nothing. Hosted Gemini anonymous callers share configured server-key quota.