Special Character Detector
Paste text to detect, highlight, and count hidden, zero-width, control, and special Unicode characters. Clean them with one click.
Instant Detection
Highlights and lists special characters as you type.
Privacy First
All analysis happens locally in your browser.
Clean Text
Remove all special characters with one click.
Frequently Asked Questions
What counts as a special character?
Any character outside standard printable ASCII, including zero-width spaces, control characters, and unusual Unicode symbols.
Can I remove all special characters?
Yes, the Clean Text button removes everything except standard printable ASCII, tabs, and line breaks.
Is my text sent to a server?
No, detection and cleaning are performed entirely client-side.
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Common Hidden Characters Reference
These are the most problematic invisible Unicode characters found in real-world text. All are detected and labelled by this tool.
| Character name | Code point | Common problem it causes |
|---|---|---|
| Zero-Width Space | U+200B | Breaks string matching, invisible in all editors |
| Zero-Width Non-Joiner | U+200C | Found in Arabic/Persian copy-paste, breaks comparisons |
| Zero-Width Joiner | U+200D | Used in emoji sequences, unexpected in plain text |
| Byte Order Mark (BOM) | U+FEFF | Corrupts first character of strings from Windows files |
| Soft Hyphen | U+00AD | Invisible hyphen from PDFs/Word; breaks string length |
| Non-Breaking Space | U+00A0 | Looks like a space but is not — fails \s regex matches |
| Right-to-Left Mark | U+200F | Reverses text direction, used in filename spoofing |
| Word Joiner | U+2060 | Prevents line breaks, invisible, from rich text editors |
When Hidden Characters Cause Real Problems
Debug Copy-Paste Issues
Text that looks identical fails comparison. Zero-width characters inserted during copy-paste from websites or PDFs are the #1 cause.
Database WHERE Clause Failures
SQL queries that should match a string but return no results — almost always a hidden character in the pasted value.
Code & Variable Name Bugs
Two variables that appear identical but behave differently — a zero-width character in one identifier makes them distinct to the compiler.
Password Authentication Errors
Passwords copied from a password manager or document may include invisible characters, making them fail even when they look correct.
API Request Failures
API keys, tokens, or JSON values pasted from emails or PDFs often carry hidden characters that cause 401 or parsing errors.
Filename Security Audits
Detect right-to-left override characters in filenames that can disguise a malicious file extension as a safe one.
How to Remove Hidden Characters
- →VS Code regex replace: Open Find & Replace (Ctrl+H), enable regex mode, search for
[\u200B-\u200D\uFEFF\u00AD]and replace with nothing. - →JavaScript:
str.replace(/[\u200B-\u200D\uFEFF]/g, '')removes the most common zero-width characters. - →Python:
import unicodedata; unicodedata.normalize('NFKC', text)normalises many special Unicode characters to their standard equivalents. - →Paste via plain text: Use Ctrl+Shift+V (paste without formatting) in most apps to strip rich-text invisible characters at the source.
Frequently Asked Questions
What are zero-width characters and why are they dangerous?
Zero-width characters are Unicode code points that take up no visible space: zero-width space (U+200B), zero-width non-joiner (U+200C), zero-width joiner (U+200D), and others. They are invisible to the human eye but present in the string. In code, they break string comparisons. In databases, they cause WHERE clause mismatches. In passwords, they make credentials appear identical but fail authentication.
Where do hidden characters come from?
The most common source is copy-pasting from websites, PDFs, Word documents, or messaging apps. Rich text editors insert invisible formatting characters. Some websites deliberately embed tracking characters. AI-generated text sometimes includes soft hyphens or non-breaking spaces.
What is a BOM (Byte Order Mark)?
The BOM is the character U+FEFF placed at the start of a file to indicate its encoding. Some Windows programs prepend this to UTF-8 files. When pasted into code or databases, it appears as a corrupt first character and is nearly impossible to spot visually.
Can hidden characters break my code?
Yes. A variable name with a zero-width space looks identical to one without but is treated as a different identifier. SQL queries with invisible characters in string literals fail to match database values. JSON keys with hidden characters cause parse errors or silent data loss.
How do I remove special characters after detecting them?
Once you identify which characters are present using this tool, use a text editor with regex support (VS Code, Notepad++) to find and remove them. The regex [-] targets common zero-width characters.
What is a right-to-left mark (RLM)?
U+200F is an invisible character that changes text direction to right-to-left. When embedded in filenames or URLs, it can be used to disguise malicious file extensions (e.g. making a .exe look like .jpg). Always check downloaded filenames for RTL/LTR marks.
Is this tool free?
Completely free. Paste any amount of text and get an instant character-by-character analysis with no limits.
What users say about Special Character Detector
Real feedback from ToolsBear users — reviewed and approved by our team.