Text Tools for Developers

Test regular expressions, compare two texts, convert naming cases, count characters and bytes, and convert full-width text.

When to use these tools

Text4 min read
Characters vs Bytes: UTF-8, EUC-KR and Shift_JIS
Text has different byte counts in UTF-8, UTF-16, EUC-KR (CP949) and Shift_JIS (CP932). See the numbers and how to fit VARCHAR and fixed-length records.
Updated 2026.10.03Related tool: Character & Byte Counter →
Text6 min read
Regex Basics: 10 Patterns and How to Avoid ReDoS
Ten regular expression patterns with tested examples, plus how catastrophic backtracking (ReDoS) happens with patterns like (a+)+ and how to rewrite them.
Updated 2026.10.03Related tool: Regex Tester →