Free Invisible Character Detector — Find Hidden Unicode Instantly

Find & Remove Hidden Characters With The #1 Invisible Character Detector

Paste your text and instantly see every invisible Unicode character hiding in it. Zero-width spaces, non-breaking spaces, ChatGPT watermarks, control characters — all exposed, all removable in one click.

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How the Invisible Character Detector Works — Paste, Scan, Clean

Invisible characters are Unicode symbols that exist in your text but don't show up visually. They take up no width, render as nothing on screen, and pass through most text editors without a trace. You can't see them. You can't select them. But they're there — and they cause real problems.

Our invisible character detector finds them all:

drop any text into the left panel. Blog posts, ChatGPT output, code, emails, copy-pasted content from any source. The detector scans everything.
the stats panel shows how many invisible characters were found and breaks them down by type (zero-width space, non-breaking space, soft hyphen, etc.). The preview panel highlights every hidden character with a visible ⚠ marker so you can see exactly where they are.
one click copies your text with all invisible characters stripped out. No markers, no hidden junk — just clean text ready to use.
How the Invisible Character Detector Works — Paste, Scan, Clean

Three steps. No configuration. Paste in, scan, copy clean. The whole thing takes seconds.

Where Invisible Characters Come From — And Why They're a Problem

Hidden characters don't appear out of nowhere. They come from specific sources, and each one creates different headaches.

Where Invisible Characters Come From — And Why They're a Problem
OpenAI's newer models (GPT-o3, o4-mini) insert hidden Unicode characters — primarily Narrow No-Break Spaces (U+202F) — into generated text. Some call these "AI watermarks." They look identical to regular spaces but have different Unicode values. If you publish AI-generated content without cleaning it, these markers are sitting in your text for anyone with a detector to find.
Rich text editors, PDFs, Word documents, and web pages all use invisible Unicode for formatting. Non-breaking spaces prevent awkward line breaks. Soft hyphens control where words split. Zero-width joiners connect characters in certain scripts. When you copy that text, the invisible characters come with it.
A zero-width space inside a variable name looks fine in your editor but throws a syntax error when compiled. A non-breaking space in a JSON value looks like a regular space but fails string comparison. These bugs are maddening because the code looks correct — the problem is literally invisible.
Hidden characters in your page titles, meta descriptions, and body text can confuse search engine parsers. Some CMS platforms don't handle invisible Unicode gracefully, leading to display issues, broken links, or indexing problems that are hard to diagnose.
Companies embed zero-width characters at specific positions in documents to track who shared or leaked content. If you distribute text with hidden watermarks and don't know they're there, you might be identifiable through the invisible pattern.

What This Detector Catches — 30+ Types of Hidden Characters

Most "invisible character" tools check for two or three character types. Ours scans for over 30 categories of hidden Unicode characters. Here's what it finds:

Zero-width space (U+200B), zero-width non-joiner (U+200C), zero-width joiner (U+200D), word joiner (U+2060), and zero-width no-break space / BOM (U+FEFF). These are the most common invisible characters — they take up no visual space but exist in the text data. AI tools and copy-paste from web pages are the biggest sources.
Non-breaking space (U+00A0), narrow no-break space (U+202F), en space, em space, thin space, hair space, figure space, and more. These look like regular spaces but have different Unicode values. ChatGPT's newer models embed narrow no-break spaces throughout generated text.
Left-to-right mark (U+200E), right-to-left mark (U+200F), and various directional embedding/override characters. These control text direction in multilingual content and often appear when copying from Arabic, Hebrew, or other RTL sources.
Soft hyphen (U+00AD), invisible separator (U+2063), line separator (U+2028), paragraph separator (U+2029), and various other Unicode control characters. These influence how text renders but are invisible to the human eye.
Each hidden character is replaced with a visible ⚠ marker in the preview panel. Hover any marker to see the character's Unicode name and code point. The breakdown card tallies each type so you know exactly what's hiding in your text.
What This Detector Catches — 30+ Types of Hidden Characters

Who Uses the Invisible Character Detector — And What They're Finding

This tool gets daily use from people who've been bitten by invisible characters before — and from people who want to catch them before they cause trouble.

Who Uses the Invisible Character Detector — And What They're Finding
If you're publishing content that was drafted with ChatGPT or another AI model, hidden Unicode characters might be embedded in the output. Publishers run the detector before publishing to strip any markers that could identify the text as AI-generated.
A zero-width space in a variable name, function parameter, or config value creates errors that look impossible — the code seems correct, the string looks right, but nothing works. Developers paste suspicious strings into the detector and find the hidden character in seconds instead of hours.
Hidden characters in page titles, URLs, alt text, and meta descriptions can cause indexing issues and display problems in search results. SEO teams scan content before publishing to catch and remove any invisible junk.
Text pulled from PDFs, websites, Word documents, and Google Docs often carries hidden formatting characters. Writers run the detector to get truly clean text before submitting to editors or publishing.
Invisible characters are used for text watermarking, fingerprinting, and even attack payloads in AI systems. Researchers use the detector to analyze suspicious text for embedded hidden patterns.

See What's Really There.

Stop Publishing Text with Characters You Can't See

You can't find what you can't see. That's the whole problem with invisible characters — your text looks fine, your editor shows nothing wrong, and the issues only appear downstream. A broken build. A weird display glitch. An AI watermark someone else detects.

The invisible character detector makes hidden characters visible. Paste your text, see every hidden character highlighted with its exact name and code point, and copy a clean version with one click.

It's free. No signup, no character limits. Paste, scan, clean. That's the entire workflow.

Frequently Asked Questions

What Are Invisible Characters?

Invisible characters are Unicode symbols that exist in text data but produce no visible output on screen. They include zero-width spaces (U+200B), non-breaking spaces (U+00A0), soft hyphens (U+00AD), directional marks, and various control characters. They serve legitimate purposes — word breaking in Asian languages, text direction in RTL scripts, non-breaking spacing — but they also show up as unwanted artifacts from copy-paste, AI tools, and document formatting.

Does ChatGPT Put Hidden Characters in Its Output?

Yes. OpenAI's newer models (GPT-o3, o4-mini) embed hidden Unicode characters in generated text, primarily Narrow No-Break Spaces (U+202F). Some people call these "AI watermarks" though OpenAI describes them as a "quirk of large-scale reinforcement learning" rather than intentional watermarking. These characters are easy to detect and remove with our tool.

How Many Types of Invisible Characters Does This Tool Detect?

The detector scans for over 30 types of hidden Unicode characters including zero-width spaces, zero-width joiners, non-breaking spaces, narrow no-break spaces, directional marks (LTR/RTL), soft hyphens, word joiners, BOM characters, various Unicode space characters (en space, em space, thin space, hair space), line/paragraph separators, and invisible math operators.

Can Invisible Characters Break My Code?

Yes — and they're one of the hardest bugs to find. A zero-width space inside a variable name, function call, or configuration value looks correct in your editor but causes syntax errors, failed comparisons, or unexpected behavior at runtime. The character is literally invisible, so the code appears fine. Pasting suspicious strings into the detector instantly reveals hidden characters that no amount of visual inspection would catch.

Where Do Invisible Characters Come From?

Common sources include: AI models like ChatGPT (which embed hidden Unicode in output), copy-paste from websites and rich text editors, PDF text extraction, Word and Google Docs formatting, multilingual content with directional marks, and intentional text watermarking. Any text that's been through multiple tools or formats is likely to carry some invisible characters.

What Does the Preview Panel Show?

The preview panel displays your text with every invisible character replaced by a visible ⚠ marker. You can see the exact position of each hidden character within your text. The stats cards above show the total count and a breakdown by character type (e.g., "Zero-width space: 3, Non-breaking space: 5"). This tells you exactly what's hiding in your text and where.

What Does 'Copy Cleaned' Do?

"Copy cleaned" copies your text to the clipboard with all invisible characters removed. It strips every hidden Unicode character the detector found and gives you clean text — no markers, no hidden junk. You can paste it directly into your editor, CMS, or code file.

Is My Text Private?

Your text is sent to our server for scanning but isn't stored permanently. We don't save your content, share it with third parties, or use it for any other purpose. Once the scan results are returned, your input is discarded.

Can This Detect AI Watermarks?

Yes. The tool detects the Narrow No-Break Space (U+202F) and other hidden Unicode characters that AI models like ChatGPT embed in their output. If your AI-generated text contains these markers, the detector will find them, show you where they are, and let you remove them with one click.

Does This Work with Code, HTML, and JSON?

Yes. The detector works with any text — code, HTML, JSON, XML, CSV, Markdown, or plain text. It's especially useful for developers because invisible characters in code cause bugs that are impossible to spot visually. Paste your code snippet, find the hidden character, and copy the clean version.