CotEditor for Mac is an open-sourced, Cocoa-based plain-text editor for OS X. It supports syntax highlighting, powerful find-and-replace with OniGmo (regular expression engine), and other small goodies for coding. It can handle also CJK languages well.
CotEditor is exactly made for macOS. It looks and behaves just as macOS applications should. CotEditor for macOS launches so quick that you can write your text immediately when you want to. The app is developed as an open-source project that allows anyone to contribute.
Features and Highlights
Syntax Highlighting
Colorize more than 50 pre-installed major languages like HTML, PHP, Python, Ruby or Markdown. You can also create your own settings.
Split Editor
Split a window into multiple panes to see different parts of your document at the same time.
Powerful Find & Replace
Super powerful find and replace using the ICU regular expression engine.
Character Inspector
Inspect Unicode character data of each selected character in your document and display them in a popover.
Setting via Click
There are no complex setting files that require geek knowledge. You can access all your settings including syntax definitions and themes from a normal preferences window.
Scriptable
Make your own macro in your favorite language, whether it is Python, Ruby, Perl, PHP, UNIX shell, AppleScript or JavaScript.
Auto Backup
You don't need to lose your unsaved data anymore. Cot Editor for Mac backups your documents automatically while editing.
Incompatible Characters
Check and list-up the characters in your document that cannot be converted into the desired encoding.
Outline Menu
Extract specified lines with the predefined syntax and you can jump to the corresponding line.
CJK Language Friendly
Estimate various file encodings accurately, toggle to vertical text mode and keep its line height correctly.
Note: Requires 64-bit processor.

CotEditor for Mac is an open-sourced, Cocoa-based plain-text editor for OS X. It supports syntax highlighting, powerful find-and-replace with OniGmo (regular expression engine), and other small goodies for coding. It can handle also CJK languages well.
CotEditor is exactly made for macOS. It looks and behaves just as macOS applications should. CotEditor for macOS launches so quick that you can write your text immediately when you want to. The app is developed as an open-source project that allows anyone to contribute.
Features and Highlights
Syntax Highlighting
Colorize more than 50 pre-installed major languages like HTML, PHP, Python, Ruby or Markdown. You can also create your own settings.
Split Editor
Split a window into multiple panes to see different parts of your document at the same time.
Powerful Find & Replace
Super powerful find and replace using the ICU regular expression engine.
Character Inspector
Inspect Unicode character data of each selected character in your document and display them in a popover.
Setting via Click
There are no complex setting files that require geek knowledge. You can access all your settings including syntax definitions and themes from a normal preferences window.
Scriptable
Make your own macro in your favorite language, whether it is Python, Ruby, Perl, PHP, UNIX shell, AppleScript or JavaScript.
Auto Backup
You don't need to lose your unsaved data anymore. Cot Editor for Mac backups your documents automatically while editing.
Incompatible Characters
Check and list-up the characters in your document that cannot be converted into the desired encoding.
Outline Menu
Extract specified lines with the predefined syntax and you can jump to the corresponding line.
CJK Language Friendly
Estimate various file encodings accurately, toggle to vertical text mode and keep its line height correctly.
Note: Requires 64-bit processor.