CotEditor Overview
CotEditor is a free, open source plain-text editor for Mac. It highlights syntax for more than 70 programming and markup languages, from HTML and Python to Markdown and Swift. Find and replace runs on the ICU regular-expression engine, powerful enough for serious search-and-replace work. Every setting lives in a standard settings window instead of a config file, covering syntax definitions, themes, and key bindings. The app launches almost instantly, splits into multiple panes for viewing different parts of a document, and includes a character inspector for checking Unicode data. Scripts in Python, Ruby, Perl, PHP, shell, AppleScript, or JavaScript can automate repetitive text tasks directly inside the app. A bundled command-line tool called cot opens and controls documents straight from Terminal.
Why Choose CotEditor Mac App
TextEdit handles basic notes fine, but it falls short the moment syntax highlighting, regex search, or scripting comes up. A full IDE like Xcode solves that, but drags in far more than a quick text file needs. CotEditor sits in between. It opens fast, highlights over 70 languages, and handles serious find-and-replace work, all without a project manager or plugin system getting in the way.
CotEditor is built only for macOS, not ported from anywhere else. It follows macOS conventions for Dark Mode, Versions, iCloud, and VoiceOver, and every setting lives in a standard settings window instead of a config file. The current version requires macOS 15 (Sequoia) or later, a higher bar than many similarly simple text editors ask for, since recent releases lean on newer macOS text-rendering and security features.
Key Features
- Syntax highlighting for 70+ languages: colorizes HTML, PHP, Python, Ruby, Markdown, and dozens more, with support for custom syntax definitions.
- ICU-powered find and replace: runs regular-expression search and replace using the same engine found in many professional tools.
- GUI-based settings: configures syntax definitions, themes, and every other setting from a standard settings window, no config files to hand-edit.
- Auto Save with backup: saves work automatically while editing, with an option to avoid overwriting the original file.
- Outline menu: extracts key lines based on the document's syntax and jumps straight to them.
- Split editor: divides a window into multiple panes to view different parts of a document at once.
- Character inspector: shows Unicode data and an enlarged glyph for any selected character.
- Multi-cursor editing: edits multiple points in a document at the same time.
- Sidebar file browser: navigates a project's folder structure directly from the sidebar.
- Scripting support: automates tasks in Python, Ruby, Perl, PHP, UNIX shell, AppleScript, or JavaScript.
- Command-line tool: opens and controls documents from Terminal using the bundled cot command.
- Incompatible character detection: flags characters in a document that can't convert into a chosen text encoding.
Screenshots
What's New in CotEditor 7.0.9 Version
Version 7.0.9, released within the past week, is a small maintenance update:
- Avoids an unnecessary scroll after inserting a snippet when the target range is already visible
- Updates the Markdown syntax to improve heading highlights
- Updates the bundled tree-sitter-scala parser to version 0.26.2
- Fixes a regex replacement bug where the "Unescape replacement text" option incorrectly removed escaped backslashes
- Fixes two LaTeX syntax issues affecting outline extraction and argument brace highlighting
- Fixes a Scala syntax issue where string interpolators were highlighted in the wrong color
- Fixes typos in the Dutch and French localizations
Supported macOS Versions
CotEditor requires macOS 15 (Sequoia) or later. That requirement reflects how actively the app is developed. Recent versions moved core syntax highlighting to a tree-sitter-based parser, added a Liquid Glass interface refresh for macOS 26 Tahoe, and lean on newer text-rendering APIs that older systems don't support. Since it's a lightweight, plain-text focused app, hardware demands stay low regardless of Mac model. The real requirement to watch is the OS version, not the processor or RAM.
How to Download and Install CotEditor on Mac?
CotEditor is also available on the Mac App Store, but installing the direct download version only takes a few steps.
- Click the Download button above to securely download the setup file.
- Open the downloaded file, then drag CotEditor into your Applications folder.
- Launch CotEditor from Applications. If macOS shows an "unidentified developer" warning, go to System Settings → Privacy & Security and click Open Anyway.
Grant permission if prompted when opening files from outside the app's sandbox, such as a folder added to the sidebar.
CotEditor opens straight to a new document, with no account or sign-in required. This direct download checks for updates itself rather than relying on the App Store, and it skips the optional donation prompts built into the App Store version.
How to Use CotEditor Mac App?
- Open a plain-text file, or start a new untitled document from the File menu.
- Choose a syntax from the toolbar menu to enable highlighting for that language.
- Use Find, accessible from the Edit menu, for a quick search or a full regular-expression replace.
- Open the sidebar to browse a project folder, or the Outline inspector to jump between key lines.
- Split the editor from the View menu to see two parts of the same document side by side.
- Save the file, or let Auto Save handle it automatically as changes are made.
Alternatives to CotEditor
Visual Studio Code: Free, actively maintained code editor with a much larger extension ecosystem and IDE-style features.
BBEdit: Offers a genuinely free unregistered mode with core text editing, alongside a paid tier for advanced features.
TextEdit: Built into every Mac at no cost, covering basic plain-text and rich-text editing without syntax highlighting.
