Text Counter
Count characters, lines, words, and bytes in real time.
Invalid Character Checker
Detect platform-dependent or problematic characters in text.
Input data is processed in your browser
Data is never sent to a server
Tool
What is an Invalid Character and Platform-Dependent Character Checker?
This tool helps you quickly identify environment-dependent or discouraged characters that may cause errors or text corruption in web forms, databases, legacy systems, and other applications.
It is useful for preparing safe data submissions and for debugging text-related issues during software development.
How to Use
- Paste the text you want to check into the input field.
- Scanning starts automatically, and problematic characters are listed.
- You can highlight affected characters and replace or remove them in bulk.
FAQ
What are platform-dependent characters?
Platform-dependent characters are characters such as enclosed numbers and special symbols that may only display correctly on specific operating systems, such as Windows or macOS. They can cause garbled text or compatibility issues in other environments.
What kinds of characters can be detected?
The tool can detect old-style Kanji characters, platform-dependent symbols, control characters (excluding tabs and line breaks), surrogate pair characters, and other potentially problematic characters.
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