A Quick Look extension for macOS. Preview code files instantly with 700+ themes that match text editors, syntax highlighted via Tree-sitter. 100% private. One-time purchase.

Hi, I made CodeLook, my first app! :) Quick Look on macOS is system wide, and it's such a convenient way to preview files, but it does not show code files well or at all. CodeLook is a Quick Look extension that renders that view with real syntax highlighted code in 700+ themes using native TextKit. It works everywhere macOS uses Quick Look: Finder, Spotlight, Open and Save dialogs, and third party apps like Raycast. It's an extension, so you can quit the app and previews keep working. Parsed, not matched: every language runs through the same tree-sitter grammars Zed and Neovim use, so each token is colored by what it actually is, not by a regex guess. It also makes it insanely fast even with huge files. No size cap, no truncation setting. A 9 MB C file with over 260,000 lines opens fully highlighted in ~1s. Highlighting runs inside the extension, no subprocess, no HTML and JavaScript. The extension asks for no permissions and has no network access at all. Themes come from Zed's registry: 700+ you browse and install from inside the app, and the whole preview is themed, not just the text. Background, gutter, line numbers and separator all come from the theme file. Pick one dark and one light theme and it follows your system appearance. Any font installed on your Mac renders in regular, bold, italic and bold italic. Plus control font size, line numbers, wrapping, and tab width. 17 file types right now (Swift, Rust, C, C++, Go, Ruby, Python, CSS, JavaScript, JSX, TSX, Shell, Lua, JSON, JSONC, JSONL, YAML). Each one gets a dedicated grammar rather than a generic highlighter. Sadly, .html and .ts can't be previewed by any third party app since macOS reserves those for its own handlers. My Swift highlighting engine/CLI (dog - edden27/dog) and tree-sitter are both open source under MIT. No analytics, no accounts, files never leave your Mac. Apple Silicon, macOS 26 or later. $4.99 one time on the Mac App Store. No subscription, no in-app purchases. Fully private. Happy to answer anything here.

congrats on shipping your first app, this is a genuinely satisfying idea to see done well. one thing I'm curious about: you said no network access at all, so how do the 700+ themes get onto the machine - all bundled at install, or a one-time download the first time you browse the theme picker?

@galdayan The themes are stored in a json file on disk. There is only a network request to get a particular theme. On every update I have a script that checks the repos for changes and updates the json to add/remove any from list.

@edden to clarify the names and the repo are listed. Then the repo contents are fetched to pull colors only.

CodeLook

Quick Look code previews with 700+ editor themes

Quick Look code previews with 700+ editor themes