System Prompt Sanitizer
Strip out token-wasting whitespace. This tool removes trailing spaces, converts tabs to spaces, and limits excessive newlines without breaking your Markdown formatting. Save tokens and lower your API costs.
- Preserves Markdown structure
- Live token-saving metrics
- No upload, no sign-up
- Runs in your browser
- No upload
- No sign-up
- Preserves Markdown
- Works offline
Related tools
Free AI and developer tools that run in your browser. Nothing uploaded, ever.
Why this tool is the best choice
Most text formatters break your markdown. This one is built specifically for AI prompts.
| Feature | TToolDeck | Manual Cleanup | Basic Formatters |
|---|---|---|---|
| Runs entirely in your browser | Yes | No | No |
| Prompts never sent to a server | Yes | No | No |
| Preserves Markdown & code indentation | Yes | No | Partial |
| Limits consecutive newlines | Yes | No | No |
| Live token-saving metrics | Yes | No | No |
| Free without paywalls | Yes | Yes | Partial |
How it works
- 1
Paste your prompt
Copy your system prompt or instruction text from your code, Word doc, or wherever you drafted it.
- 2
Automatic cleanup
The tool instantly converts tabs to spaces, strips trailing spaces, and removes excessive blank lines.
- 3
Copy the clean text
See exactly how many characters and lines you saved, then copy the sanitized prompt to your AI app.
Everything you get for free
Lower API Costs
LLMs charge per token. Removing hundreds of trailing spaces and blank lines directly reduces your API bill on every single request.
Better LLM Performance
Excessive whitespace can confuse context windows. Clean prompts lead to more consistent instruction following.
100% Secure
Your system prompts contain your secret sauce. Because this runs locally, your intellectual property never leaves your device.
Safe for Markdown
Unlike basic trim tools, we preserve the indentation required for Markdown lists and code blocks. We only remove trailing spaces.
Tab Conversion
Tabs count differently than spaces in some tokenizers. We standardize them to spaces for predictable token counts.
Real-time Feedback
Watch the character count drop as you type or paste, giving you instant feedback on how much bloat you removed.
What people use it for
API Cost Optimization
If your app sends a 2,000-token system prompt on every request, shaving off 200 tokens saves 10% on your bill.
Copy-Pasting from Word
Word documents and Google Docs are full of invisible formatting. Paste here to strip it all out.
Fixing Ragged Text
If you drafted a prompt in an IDE and it has auto-indentation, use this to flatten it out safely.
Preparing Prompt Templates
Clean up your base prompt templates before passing them into LangChain or LlamaIndex.
Instruction Formatting
Ensure your numbered lists and bullet points are tightly formatted so the AI parses them correctly.
Educational
Learn how much invisible whitespace exists in typical copy-pasted text and how it affects token counts.
Questions people ask
Why should I sanitize my prompt?
LLMs count every single space, tab, and newline as tokens. Removing excessive whitespace from copy-pasted text can save you hundreds of tokens per request, which directly lowers your API costs and speeds up response times.
Does this break Markdown or code blocks?
No. It only strips trailing spaces at the end of lines and limits consecutive blank lines to two. It preserves the exact indentation required for Markdown lists and code blocks.
Does it run on a server?
Never. The entire sanitization process runs locally in your browser using JavaScript regex. Your proprietary system prompts are never uploaded.
What does it do to tabs?
It replaces tabs with standard spaces. Tabs can sometimes tokenize unpredictably depending on the model. Spaces are safer and more consistent.
Will this remove all my line breaks?
No. It only removes excessive line breaks. If you have three or more empty lines in a row, it will compress them down to two, which is plenty for readability.
Is there a limit on prompt size?
Because it runs locally, the limit is your browser's memory. It can easily handle prompts that are hundreds of thousands of characters long.
Can I use this for user messages?
Yes. While it is designed for system prompts, it works just as well for cleaning up long user messages or RAG context before sending it to the model.
Will my prompt lose its meaning?
No. We only remove invisible whitespace. The actual words, punctuation, and formatting remain exactly the same.