Don's Tools · Developers · Prompt Cleaner

Prompt cleaner

Paste messy or copied text and get clean plain text for your prompts and datasets. Strip markdown, fix smart quotes, collapse whitespace and remove invisible characters, all in your browser.

What to clean

Prompt Cleaner turns messy or copied text into clean plain text, ready for prompts and datasets. Choose what to apply: strip markdown formatting while keeping the words, collapse repeated spaces and blank lines, straighten curly quotes and long dashes, convert non-breaking spaces and remove the invisible and zero-width characters that often hide in web text. It shows a live character count and how much was removed, and everything runs in your browser with nothing uploaded.

Files are processed in your browser and never uploaded.

How to use Prompt cleaner

  1. Add your text

    Type or paste your text into the input box. Everything is handled by your own browser, so nothing is sent to a server.

  2. Set the options

    Choose Straighten smart quotes and dashes, Trim trailing spaces on each line, Remove emoji and Remove all blank lines. The options are visible from the start, not hidden until you paste something.

  3. Read it and keep a copy

    The output updates as you type, so there is nothing to submit and nothing to wait for. Copy cleaned text puts the result on your clipboard.

What this tool does

Strip markdown while keeping the words

Markdown syntax is stripped while the words are kept, so a copied answer becomes plain text without losing its content.

Collapse extra spaces and blank lines

Runs of spaces collapse to one and stacked blank lines collapse to a single break, which is what makes pasted text look untidy.

Straighten smart quotes and long dashes

Smart quotes, curly apostrophes and long dashes are straightened to their plain equivalents, which is what most parsers and datasets expect.

Remove invisible and zero-width characters

Zero-width and other invisible characters are removed. They travel with copied text and are a common cause of a prompt or a CSV behaving oddly.

Live character count and amount removed

The character count and how much was removed are both shown, so you can see the effect rather than trust it.

Frequently asked questions

Is my text uploaded or saved?

No. All the cleaning happens in your browser with text replacements. Nothing you paste is sent anywhere or stored.

What does it actually clean?

It can strip markdown formatting, collapse repeated spaces and blank lines, straighten curly quotes and long dashes, and remove invisible or zero-width characters that often sneak in from copied web text. You choose which of these to apply.

Why remove invisible characters?

Copied text frequently contains zero-width spaces, non-breaking spaces and direction marks that you cannot see. They can waste tokens, break matching and cause odd formatting in prompts or datasets, so removing them gives you clean plain text.

Does stripping markdown delete my content?

No, it only removes the formatting marks. Headings keep their words, links keep their text, bold and italic keep the inner text, and lists keep the items, just without the symbols around them.

Is this good for preparing prompts or training data?

Yes. Normalising whitespace, quotes and hidden characters makes prompts and dataset text consistent and predictable, which is exactly what you want before sending it to a model or saving it.

Last updated: