Free & 100% Client-Side
Free AI Prompt Tools
Four free, client-side tools to generate, inspect, upgrade, and adapt your prompts for ChatGPT, Gemini, Claude, Midjourney, and AI video generators. Nothing leaves your browser.
100% Private, Client-Side Heuristics
Every tool runs directly inside your browser. We never send your pasted prompts to external AI APIs (OpenAI, Gemini, Anthropic) or backend servers. No accounts, no prompt tracking.
Prompt Idea Generator
No idea yet? Get a random, ready-to-use prompt from PromptUp's library, filtered by category and AI tool.
- Filter by category & AI tool
- Re-roll for another idea
- One-tap copy & full card link
Prompt Analyzer
Audit and score any prompt against 7 concrete quality signals before running it. Get actionable suggestions to eliminate ambiguity.
- Checks role, task verbs & context
- Audits format & negative constraints
- Flags vague filler words
Prompt Optimizer
Turn rough, vague instructions into well-formed, production-ready prompts using the site's official 5-part scaffold with side-by-side comparison.
- Injects authoritative expert personas
- Adds bracketed [FIELD] placeholders
- Side-by-side before & after view
Prompt Converter
Translate prompt framing between ChatGPT/Claude conversational style, Midjourney parameters, and AI video generators like Veo and Kling.
- Conversational to Midjourney tags
- Image prompt to AI Video shot list
- Strips or appends aspect-ratio flags
Which prompt tool should you use?
| Your Goal | Recommended Tool | Key Benefit |
|---|---|---|
| You don't have a prompt yet and want a random idea to start from. | Prompt Idea Generator | Random, ready-to-use prompt from the library, filtered by category and AI tool. |
| You wrote a prompt and want to verify if it is missing important guardrails. | Prompt Analyzer | Checklist of 7 core signals: role, task, context, format, constraints, filler words, and length. |
| You have a rough 1-sentence idea (e.g. "write a cold email") and need a complete prompt. | Prompt Optimizer | Transforms brief requests into a complete 5-part prompt scaffold with bracketed variables. |
| You want to adapt a prompt written for ChatGPT into Midjourney or a Veo video script. | Prompt Converter | Translates phrasing styles, strips conversational boilerplate, and adds platform parameters. |
| You want to explore pre-tested, curated prompts for specific use cases. | Prompt Library | Browse 1,410+ ready-to-use prompts with copy-paste buttons and tips. |
Learn the fundamentals of prompt engineering
Want to write better prompts from scratch? Read our comprehensive tutorial How to Write a Good AI Prompt, which walks through the 5-part formula with before-and-after comparisons across text, photo editing, image generation, and video.
Frequently asked questions
Are these AI tools free to use?
Yes, all four tools on PromptUp are 100% free with no account or sign-up required.
Is my prompt data private?
Yes. Every tool runs entirely in your browser using local client-side heuristics. No text is ever sent to external AI servers or logged anywhere.
Which tool should I use first?
If you don't have a prompt yet, use the Prompt Idea Generator for a random starting point. If you have an existing prompt, use the Prompt Analyzer to check for missing signals. If you only have a rough idea, use the Prompt Optimizer to build a structured 5-part prompt. If you want to switch between ChatGPT and Midjourney or Veo, use the Prompt Converter.
Do these tools work on mobile devices?
Yes. All tools are fully responsive and work seamlessly on phones, tablets, and desktop browsers.