Stop guessing whether your new prompt is better. Test both versions side by side and keep the one that wins.

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Free to start. Run your first head-to-head comparison in under two minutes.

Most prompt tools help you write a prompt and call it done. They generate a polished version, you copy it, and you have no idea whether it beats the one you started with until you've burned a week of real work on it.

PromptProof closes that loop. Every prompt you build can be run against the model live, compared side by side with its older versions, and scored on the output it produces. You stop trusting that a prompt is better and start seeing it.

That single shift, from writing prompts to proving them, is what separates a prompt you hope works from one you know works.

A prompt can read beautifully and still produce mediocre output.

Polished prompts feel productive. They're full of role framing, structure, and tidy formatting. The trouble is that none of that tells you whether the output is any good, and the only way to find out is to run it. Here's where prompt tools leave you stuck:

• They optimize blind. A tool rewrites your prompt into a "better" version with no test that the output improved at all, so you're trusting the rewrite on faith.
• The models disagree. A prompt that sings in ChatGPT can flop in Claude or Gemini, and you won't know until you've shipped it on the wrong one.
• Version history without results is just clutter. Keeping every version is useless if you can't see which one produced the best answer.
• Your library fills with untested prompts. Over time you save dozens of prompts and have no record of which ones earned their place.

So you end up with a pile of clean-looking prompts and a quiet suspicion that half of them aren't pulling their weight.

Introducing PromptProof

PromptProof is a workspace for building, testing, and proving AI prompts. You write or generate a prompt, create variations, and run them against the same input across ChatGPT, Claude, and Gemini at once. The outputs appear side by side so you can pick the winner on evidence. Every tested version is scored and saved to a library that records what each prompt produced, so the prompts you reuse are the ones you've confirmed work.

What You Get for $12/mo

• Side-by-Side Output Testing. Run two or more prompt versions against the same input and read the outputs next to each other, so the better prompt is obvious instead of assumed.
• Multi-Model Comparison. Test the same prompt across ChatGPT, Claude, and Gemini in one pass and see which model handles it best before you commit.
• The Prompt Generator and Optimizer. Turn a rough idea into a structured prompt, then generate optimized variations to test against each other rather than accept on faith.
• Results-Linked History. Every version is stored with the output it produced, so your history shows you which prompt won and why.
• Reverse Prompting. Turn an image, a URL, or a piece of text you like into a prompt you can reuse and adapt.
• The Proven Library. Save prompts to a library that marks which ones have been tested and how they performed, so reuse is grounded in evidence.
• Reusable Templates with Variables. Build prompts with fill-in fields so a winning prompt becomes a template your whole team can run.
• Team Workspace. Share proven prompts across your team, so everyone reaches for the version that's already been confirmed to work.

Why I'm Charging $12

PromptProof runs at $12 a month for the full workspace, including the model testing that costs real compute on our end. The comparable tools sit around $10 to $15 for prompt building alone, without running the prompts against the models for you.

The reason it's worth a couple of dollars more is the testing itself. One prompt you proved before shipping it into a client deliverable or a production feature saves more than a year of the subscription. The proof is the product.

Who This Is For

PromptProof fits you if:
- You write prompts for real work, client deliverables, content, code, or product features, and the quality of the output matters.
- You've optimized a prompt, felt good about it, and later wondered whether it was better than what you had.
- You work across more than one model and want to know which one to use for a given job.

Look elsewhere if:
- You write the occasional casual prompt and don't need to confirm anything. A free generator covers you.
- You want a giant marketplace of pre-written prompts to browse. PromptProof is a workspace for proving your own, not a prompt store.

The Guarantee

The Proof Guarantee

Use PromptProof for 30 days, run your real prompts through it, and if the side-by-side testing hasn't shown you at least one case where the version you would have shipped was beaten by another, you get a full refund. Seeing that gap once tends to change how you work, and we're confident you'll see it.

In Your First Session, You'll Have:

• A head-to-head test of two prompt versions on the same input
• The same prompt compared across ChatGPT, Claude, and Gemini
• A clear winner chosen on output instead of appearance
• A rough idea turned into a structured, optimized prompt
• An image or URL reverse-engineered into a reusable prompt
• Your best prompt saved to a library that records its results
• A template with variables your team can run on their own

If You're Skimming

What it is: A prompt workspace that lets you test prompt versions side by side across ChatGPT, Claude, and Gemini, so you keep the prompt that proves it performs instead of the one that just reads well.

What you get: Side-by-side output testing, multi-model comparison, a generator and optimizer, results-linked history, reverse prompting, and a library that records what each prompt produced.

Price: $12/mo for the full workspace. Free tier to start. Cancel anytime.

Catch: This is a workspace for proving your own prompts, not a marketplace of pre-written ones.

Guarantee: See the testing beat a prompt you would have shipped within 30 days, or your money back.

Start testing prompts free

The reason prompt libraries fill up with prompts nobody trusts is that they record what you wrote, never what it produced. PromptProof saves the output alongside the prompt, so your library becomes a record of what works rather than a folder of hopeful drafts.

Already happy with your prompts? Run your three best ones through a side-by-side test against ChatGPT, Claude, and Gemini. Most people find at least one that performs far better on a model they weren't using, which is the cheapest quality upgrade available to them.