Free Toolkit

Zero-Width Character DetectorDetect and remove hidden zero-width and invisible characters in text.

Zero-Width Character Detector illustration
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Zero-Width Character Detector

Detect and remove hidden zero-width and invisible characters in text.

How to Use
1

Paste Text

Paste text that may contain hidden invisible characters.

2

View Detection Results

See a list of all invisible characters found with their positions and types.

3

Get Cleaned Text

Copy the cleaned text with all invisible characters removed.

What Is Zero-Width Character Detector?

A zero-width character detector scans text for hidden invisible Unicode characters that can't be seen but affect text processing. It detects Zero-Width Space (U+200B), Zero-Width Non-Joiner (U+200C), Zero-Width Joiner (U+200D), Word Joiner (U+2060), BOM (U+FEFF), Soft Hyphen (U+00AD), and many other invisible format characters. These hidden characters can cause bugs in code, break string comparisons, corrupt data, and are sometimes used maliciously in homograph attacks or text manipulation.

Why Use Our Zero-Width Character Detector?

  • Detects 15+ types of invisible Unicode characters
  • Shows exact position and type of each hidden character
  • Provides cleaned text with invisible characters removed
  • Essential for debugging string comparison issues
  • Detects potential text manipulation or watermarking

Common Use Cases

Code Debugging

Find invisible characters causing compilation errors, failed comparisons, or unexpected behavior.

Data Cleaning

Detect and remove invisible characters from database entries, CSV files, and imported data.

Security Analysis

Detect invisible characters used in phishing, homograph attacks, or text manipulation.

Copy-Paste Cleanup

Find invisible characters that snuck in when copying text from websites or documents.

Technical Guide

The detector scans each character's Unicode code point against a known list of invisible/zero-width characters. It checks for Zero-Width Space (U+200B), Zero-Width Non-Joiner (U+200C), Zero-Width Joiner (U+200D), Left/Right-to-Right Marks (U+200E/200F), Word Joiner (U+2060), Invisible Math Operators (U+2061-2064), BOM (U+FEFF), Soft Hyphen (U+00AD), Combining Grapheme Joiner (U+034F), Arabic Letter Mark (U+061C), and Mongolian Vowel Separator (U+180E). Each detected character is logged with its position, Unicode code point, and human-readable name. The cleaned output is generated by filtering out all detected invisible characters.

Tips & Best Practices

  • 1
    Always check pasted code for invisible characters if you get unexpected errors
  • 2
    Zero-width characters in passwords can make them appear to match when they don't
  • 3
    Text copied from websites often contains hidden formatting characters
  • 4
    JSON and CSV data can be corrupted by invisible characters in field values
  • 5
    Use this tool as a first step when debugging "works on my machine" string issues

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Frequently Asked Questions

QWhy can't I see zero-width characters?
They have no visual representation — they're designed to be invisible while affecting text processing (line breaking, joining, etc.).
QHow do invisible characters get into my text?
They can be introduced by copy-pasting from websites, text editors, PDFs, or by text processing tools.
QCan invisible characters cause bugs?
Yes, they can cause string comparison failures, JSON parsing errors, database issues, and code compilation errors.
QAre invisible characters malicious?
They have legitimate uses (typography, emoji combining) but can be used maliciously in phishing URLs, fake content, and data manipulation.
QWhat's the most common invisible character?
Zero-Width Space (U+200B) is the most common, often introduced by copy-pasting from web pages.

About Zero-Width Character Detector

Zero-Width Character Detector is a free online tool from FreeToolkit.ai. All processing happens directly in your browser — your data never leaves your device. No registration required. No ads. Just fast, reliable tools.