404
built-in file types
Finder Quick Look, upgraded
PreviewanytechnicalfilewithatapofSpace.
One native macOS app for dotfiles, configs, markdown, logs, plain text, and source code — right in Quick Look.
599
registered extensions
295
filename mappings
53
highlight query files
Why dotViewer
One app. Replaces several Quick Look plugins.
Instead of stacking a markdown previewer, a plain-text viewer, and a syntax-highlighting add-on, install one signed app and get the whole technical-file surface at once.
.gitignore.envREADME.mdpackage.jsonDockerfile.editorconfigYAMLXMLplistCSV / TSVshell scriptsman pageslog filesSwift, C, Go, TS…
Code & config
Syntax-aware previews for the files you actually open.
Token-level highlighting, line numbers, a language badge, and a copy action — without ever leaving Finder.
- Swift, C, Go, TypeScript, Python, Rust + 100 more
- JSON, YAML, TOML, INI, XML with structure-aware colour
- Shell scripts, Dockerfiles, Makefiles, Procfiles
Markdown
Read rendered. Inspect raw. One key away.
Toggle between styled output and the source with a keystroke. Table of contents, code blocks, tables — all rendered natively.
Install
Two ways. Takes a minute.
Homebrew or the direct DMG — same signed, notarized binary. Pick whichever matches your taste.
Install with Homebrew
Paste this into Terminal. Homebrew downloads the notarized DMG, copies dotViewer into /Applications, and registers the Quick Look extensions automatically.
$brew install --cask stianlars1/tap/dotviewer
New to Homebrew? brew.sh has the one-line installer. Cask source lives at github.com/Stianlars1/homebrew-tap.
01
Install with one command
Homebrew downloads the notarized DMG, drops dotViewer into Applications, and registers the Quick Look extensions.
02
Or drag the DMG into Applications
Prefer the classic path? The signed DMG is the same binary, shipped straight from GitHub Releases.
03
Press Space on any file
First launch registers the extension. After that, Quick Look does the rest — from Swift to .env to man pages.
Companion app
Everything tunable, in one place.
Themes, font families, layout, copy behaviour, file-type mappings, and conflict resolution — consolidated into a single settings surface.
Coverage & honest limits
Broad where it helps, honest where macOS still wins.
dotViewer improves Quick Look wherever third-party extensions are allowed. Where macOS owns the preview path, the limitation is stated directly.
404+built-in file types
599+registered extensions
295+exact filenames
4macOS routing caveats
Known routing caveats
.html stays with the native HTML Quick Look renderer. macOS routes it system-first, so third-party extensions can't override it.
.ts is claimed by macOS as MPEG-2 transport stream video — a platform routing quirk, not a dotViewer bug.
Both have an answer since 1.5.0. Press ⌥Space instead of Space and dotViewer opens its own preview window — same highlighting, same themes, on any text file macOS won't route. Space is never intercepted, so native Quick Look keeps working exactly as it does today.
Need a type that isn't shipped? Open an issue on GitHub and it lands in a future release.
Support checker
Check if your file type is supported.
Search extensions, filenames, and language aliases. Caveats are listed inline when macOS still owns the preview path.
Support checker
Check a file type before you install.
Type an extension like .cue, an exact filename like Dockerfile, or a language name like yaml. The result below uses the same shipped support list and macOS routing caveats the site exposes in full further down the page.
Static shipped coverage: 404 file types, 599 extensions, and 295 exact filename mappings.
Ready to check
Start with a real extension, filename, or language name and dotViewer will check the shipped list instantly.
FAQ
Short answers before installation.
What files is dotViewer built for?
dotViewer is built for the technical text files developers keep hitting Space on in Finder: dotfiles, config files, markdown documents,
CSV / TSV data, man pages, logs, extensionless executable scripts, plain text documents, and source code.Can dotViewer preview dotfiles like .gitignore and config files like JSON, YAML, XML, and INI?
Yes. The app is designed around exactly that workflow, including
.gitignore, .env, .editorconfig, package.json, YAML, XML, plist, TSV, man pages, log files, extensionless executable scripts, and many other text-based formats.Why use dotViewer instead of separate markdown or code preview extensions?
One signed app replaces the stack — markdown plugin, plain-text plugin, syntax highlighter. One settings surface, one install flow, one thing to update.
Does it override every file type?
No. Some types are owned by macOS system handlers and no third-party extension can claim them. For those, press
⌥Space instead — dotViewer opens its own preview window on any text file, whether or not macOS will route it.What does ⌥Space do?
It opens dotViewer's own preview window for the file selected in Finder — the same syntax highlighting, themes and fonts as the Quick Look preview, but on any text file, including the ones macOS refuses to route.
.ts is the clearest example: macOS claims it as MPEG-2 transport stream video, so no Quick Look extension can ever see it. Space itself is never intercepted — native Quick Look keeps behaving exactly as it does today. Added in 1.5.0.Is the app signed and notarized?
Yes. The DMG is Developer ID signed and Apple-notarized, so Gatekeeper is happy on a normal Mac. The same binary ships via the Homebrew cask.
Can I install dotViewer with Homebrew?
Yes. Run
brew install --cask stianlars1/tap/dotviewer and Homebrew installs the notarized DMG and registers the Quick Look extensions automatically. brew upgrade --cask picks up new releases.Is dotViewer free or paid?
Free. The direct DMG and the Homebrew cask are the same signed, notarized build, at no cost. If it saves you time, sponsoring development on GitHub is the way to support it.
Can I choose the preview font?
Yes. dotViewer lets you pick installed macOS fonts separately for code/RAW previews and rendered markdown. The code choice also carries through Finder thumbnails.
Another Quick Look extension is overriding dotViewer. How do I fix it?
The Status screen includes a built-in conflict scanner that detects competing Quick Look extensions and lets you resolve them in one click. For manual inspection you can also use the free PluginKits app. Both approaches take effect immediately.
Can I add my own file types?
You can override highlighting for any type dotViewer already ships. Brand-new types need a release update — file a GitHub issue and they get added.
A better Quick Look workflow for technical files.
Inspect the file, understand what it is, keep moving.