JSON you can read
A collapsible tree with counts and a peek at each object. A broken file shows the exact line and column, with the offending spot marked.
macOS · Open source · Free
Press Space.
See it properly.
A Quick Look extension for developer files: JSON as a tree, Markdown rendered, logs as a colour-coded table, code highlighted — right in Finder.
Previews for
- JSON
- Markdown
- Logs
- TSV
- XML
- PowerShell
- Batch
- Swift
- Python
- Rust
- Go
- YAML
In numbers
- Lines of Swift
- —
- Unit tests
- —
Counted from the source code and updated automatically with every change.
What Loupe does
Markdown, rendered
Headings, tables, task lists and highlighted code blocks. Remote images stay blocked, so a preview never phones home.
Logs at a glance
Time, level, source and message in columns; seven formats, from nginx to JSON Lines. Big logs are read from the end, where the news is.
Code in 20+ languages
Swift, Python, Go, Rust, SQL, YAML and more, plus PowerShell, Batch and 13 XML dialects that macOS would otherwise never show.
You decide
Switch Loupe off globally or per category — Markdown, JSON, tables, logs, code. Off means plain text, exactly as without Loupe.
Private and fast
Sandboxed, read-only, offline, and not a single byte of JavaScript in a preview. Light and dark mode, English and German.
What it looks like
JSON tree
Every object with its key count and a peek at its content.
JSON errors
The exact position of the problem, with the lines around it.
Markdown
Rendered like on GitHub, in your system's appearance.
Log files
Levels counted in the toolbar, errors tinted with their stack trace.
Tables
TSV laid out as a table, numbers aligned on the right.
Source code
Highlighting with line numbers and the language badge.
PowerShell
Variables, cmdlets, parameters and here-strings.
XML
Elements, attributes, CDATA and entities, each in its own colour.
The companion app
Switches per category, appearance, text size and language.
Install in three steps
-
1
Download
Get the ZIP above and unpack it.
-
2
Move and open
Drag Loupe.app to Applications. The app is not notarized: open it once with right-click → Open.
-
3
Turn it on
System Settings → General → Login Items & Extensions → Quick Look → enable Loupe. Then press Space on a file.
Check what you downloaded
- Loupe-v0.5.1-macOS.zip
13cc645893ae5b7951c282d6169fc30d036958cf012583f45b71e0430371aff4
Loupe is ad-hoc signed, not notarized — there is no Apple Team ID to check. Compare the SHA-256 of your download with the value above; the release on GitHub lists the same checksum.
On macOS 14 the switch is under Privacy & Security → Extensions → Quick Look. Stuck on plain text? Run qlmanage -r && qlmanage -r cache once.
Questions
Is Loupe free?
Yes. It is free and open source under the MIT licence, with no ads, no account and no tracking.
Why isn't it in the App Store?
Loupe is a small open-source project without a paid Apple developer account. That is also why it is not notarized and needs right-click → Open on the first launch.
What do I need?
A Mac with Apple silicon and macOS 14 Sonoma or later.
Why does my .csv file still look plain?
macOS reserves CSV for its own preview, and no extension gets asked. Save the table as .tsv and Loupe shows it. A few other types (.ts, .tsx, .scss …) never reach extensions either.
How do I update?
Download the new ZIP from this page and replace Loupe.app in Applications. Your settings stay.
Does Loupe send my files anywhere?
No. The extension runs sandboxed and read-only, has no network access in its previews and contains no JavaScript. Remote images in Markdown stay blocked.
Like the app?
Loupe is free, has no ads and stays that way. A small donation keeps it maintained — and a review of celox.io on Google helps just as much.