Syntax Highlighting: Colorize more than 50 pre-installed major languages like HTML, PHP, Python, Ruby or Markdown. You can also create your own settings.
Outline Menu: Extract specified lines with the predefined syntax, and you can jump to the corresponding line.
Powerful Find & Replace: Super powerful find and replace using the ICU regular expression engine.
Split Editor: Split a window into multiple panes to see different parts of your document at the same time.
Incompatible Characters: Check and list-up the characters in your document that cannot convert into the desired encoding.
CJK Language Friendly: Estimate various file encodings accurately, toggle to vertical text mode and keep its line height correctly.
Open Source: CotEditor is developed as an open-source project that allows anyone to contribute. (GitHub https://github.com/coteditor/CotEditor )