PROMPTMETHEUS

Promptmetheus is a "Prompt Engineering IDE" for composing, testing, and optimizing LLM prompts, letting teams break prompts into modular sections (context, task, instructions, samples, primer) and test them against 150+ LLMs from 15+ API providers side by side. Its evaluation tools include custom evaluators, completion ratings, and visual statistics for comparing prompt variants objectively rather than eyeballing outputs, plus real-time team workspaces, shared prompt libraries, dataset testing, version history, and cost calculation across providers. Export options cover CSV, JSON, and Excel for further analysis. Pricing runs Playground/Forge (free, limited), Single ($29/mo, 7-day trial), and Team ($99/mo for 3 users, $19/mo per additional seat) — with users supplying their own API keys for inference costs on top. Good fit for a team that wants to systematically test prompt variations across multiple models before shipping, rather than relying on manual trial-and-error in a single provider's playground.