English Letter Case Converter
大小写转换大写小写字母转换
Convert text to UPPERCASE or lowercase in one click, with mixed Chinese-English support and instant copy. Ideal for titles, data cleanup and copyediting, fully local.
All processing is done locally in your browser. No data is uploaded.
How to Use
- Paste any valid JSON, supports nesting, arrays and escapes
- Click Beautify to auto indent and format
- Click Minify to remove whitespace into one line
- All operations run locally for privacy
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FAQ
Which conversion modes are supported?
Full UPPERCASE and full lowercase; digits, punctuation and Chinese characters remain unchanged.
Does converting alter the original?
No, the input stays intact and results appear below for copying or clearing at any time.
Will my data be uploaded?
No, all conversions run locally in your browser.