Private. Offline. Pay once.

Turn a rough AI prompt into one that gets better answers.

Paste what you'd normally type. Prompt Optimizer rewrites it into six clear sections (Role, Goal, Context, Constraints, Output Format, Examples), scores it, and saves it to your own library. It runs in your browser, with no account and no subscription.

Try the free demo Get the full version for $19

Founding price for the first 50 buyers (regular $29). 14-day refund. Works offline.

Before

write a cold email to a recruiter at a fintech startup, i'm a junior dev, keep it short and not desperate

After

Role: You are a career coach who writes concise, human outreach emails.
Goal: Write a cold email to a fintech recruiter.
Context: I'm a junior developer with 1 year of experience.
Constraints: - Under 120 words. - No buzzwords. - Do not sound desperate.
Output: Subject line, then a plain-text body.

"Can't I just ask ChatGPT to improve my prompt?"

You can, and for a one-off it's fine. This is for people who write prompts every week and want the same quality each time:

Consistent structure. Every prompt gets the same six sections, so nothing important is forgotten.
A quality score with fix tips. See what's missing before you send it, not after a weak answer.
A library you own. Save, tag and reuse your best prompts and templates, with {{variables}} for reuse.
Private by design. The rewrite runs on your computer. Nothing is uploaded unless you choose the optional AI pass.
No subscription. One payment, and the files are yours.

Honest note: if you only write a prompt once a month, you probably don't need this. Try the free demo and see.

What's inside

Offline rewrite

Rules turn a rough prompt into Role, Goal, Context, Constraints, Output Format and Examples. Every section is editable.

Quality score

A score out of 100 with specific fixes: missing role, vague wording, no measurable limit, unfilled placeholders.

Prompt library

Save, tag, search and favorite. Export and import as JSON for backups or another computer.

9 templates + variables

Cold email, code review, blog post, summary, data analysis and more. Fill in {{variables}} and copy.

Claude, GPT, Gemini formats

Output as Claude-style XML tags, GPT Markdown, labeled blocks, plain text or JSON. Copy or download.

Before / after diff

See exactly what changed, inline or side by side. Undo, redo and session history included.

Custom rules

Add your own role presets, keywords and default sections so it learns your vocabulary.

10 color themes

Five light and five dark themes, all checked for readable contrast.

Optional AI pass

Bring your own OpenAI or Anthropic key for a deeper rewrite. Your key is stored only in your browser.

See it

Structured prompt shown as six editable sections — Six editable sections

Before and after diff view — Before / after diff

Prompt library in a dark theme — Library, in a dark theme

Pricing

One payment. No subscription. 14-day refund.

Lite

Free

Offline rewrite
3 templates
Quality score (top 2 tips)
2 output formats

Open the demo

Personal

$19 $29

Founding price for the first 50 buyers (regular $29)

Everything in Lite, unlocked
Prompt library with import / export
All 9 templates + variables
Claude / GPT / Gemini / JSON formats
Custom rules, 10 themes, AI pass (your key)
12 months of updates

Get Personal

Pro

$49

Includes the Freelance Marketing & Content Prompt Pack

Everything in Personal
104 ready-to-use prompts for freelance marketing and content
Lifetime updates to version 1.x
Priority email support

Get Pro

Single-user license: use it for your own work and client work. Need several seats? Message me on Contra.

Questions

Is the free demo really free?

Yes. No sign-up, no time limit. It has fewer templates and output formats, and it can't save a library or download files. Your text stays in your browser.

Does it use AI?

The built-in rewrite uses rules that run on your computer. It's fast and works offline, but it is not an AI model, so always read the result. An optional AI pass lets you send your prompt to OpenAI or Anthropic with your own API key for a deeper rewrite. You pay those providers directly.

Where is my data stored?

In your browser's local storage on your computer. There is no account and no server. If you clear your browser data the library is erased, so use Export JSON for backups.

What do I receive?

A ZIP file. Unzip it and double-click index.html. No install, no build step. It runs in current Chrome, Edge, Firefox and Safari.

What's the license?

One person may use it, for their own work and for client work. Please don't share or resell the files. The full text ships in the ZIP.

What if it isn't right for me?

Ask within 14 days of purchase and you get a refund (Message me on Contra).

Will it work with Claude, ChatGPT and Gemini?

The prompts it produces are plain text, so they work in any chat model. It also has output formats tuned for each (for example XML tags for Claude).