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macOS ships with a plain-text preview for .csv files. CSV Quick Look replaces it with a spreadsheet-style view that handles files with hundreds of thousands of rows without breaking a sweat — just press Space in Finder.

Features

• Instant preview — press Space on any .csv or .tsv file in Finder

• Virtual scroll — only visible rows are in the DOM; handles 500k+ row files smoothly

• Column sort — click any header to sort ascending/descending (numeric-aware)

• Row filter — live search across all columns, Escape to clear

  

• Auto-detect delimiter — comma, tab, semicolon, or pipe, chosen automatically

• Encoding support — UTF-8, UTF-8 BOM, UTF-16 LE/BE, Windows-1252, Latin-1

• Dark mode — follows the system appearance automatically

  

• Row numbers — always visible as a sticky left column

• Truncation notice — shown when the file exceeds the configured row limit

Requirements

macOS	12 Monterey or later
Xcode	15 or later (to build from source)

No dependencies. No network access. Fully sandboxed.

Install

Homebrew (recommended)

brew install --cask adamorad/tap/csv-quick-look

Then enable the extension:

System Settings → Privacy & Security → Extensions → Quick Look → enable CSV Quick Look

On macOS 12–13: System Preferences → Extensions → Quick Look.

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Build from source

If you prefer to build yourself (e.g. to customise the bundle ID):

1. Clone

git clone https://github.com/adamorad/csv-quick-look.git
cd csv-quick-look

2. Update the bundle ID (optional)

In project.yml, change the bundleIdPrefix to your own reverse-domain:

options:
  bundleIdPrefix: com.yourname   # ← change this

3. Open in Xcode and run

open CSVQuickLook.xcodeproj

Select the CSVQuickLook scheme → My Mac → ⌘R. The app installs the extension on launch.

4. Enable the extension as above.

Settings

Launch CSV Quick Look.app at any time to adjust:

Setting	Default	Description
Auto-detect delimiter	On	Detects comma, tab, semicolon, or pipe. When off, comma is used.
Max rows to display	100,000	Upper limit for the preview. Higher values use more memory.

How it works

The extension is a standard QLPreviewingController backed by a WKWebView:

1. Swift reads the file, detects encoding and delimiter, parses the CSV on a background thread.
2. It loads a local preview.html into the web view.
3. Once the page is ready, it calls initTable(headers, rows, …) via JS injection.
4. JavaScript builds a virtual-scroll table — only rows in the viewport touch the DOM.

Project structure

csv-quick-look/
├── Shared/
│   └── CSVParser.swift               # Encoding detection, delimiter sniff, RFC 4180 parser
├── CSVQuickLook/
│   ├── App.swift                     # SwiftUI app entry point
│   └── ContentView.swift             # Settings UI
├── CSVQLExtension/
│   ├── PreviewViewController.swift   # QLPreviewingController + WKWebView bridge
│   └── Resources/
│       ├── preview.html              # Page shell
│       ├── style.css                 # Light + dark themes
│       └── table.js                  # Virtual scroll, sort, filter
└── project.yml                       # XcodeGen spec

Contributing

Pull requests are welcome. Open an issue first for significant changes.

The JS/CSS frontend can be iterated without rebuilding the Swift target — edit the files in CSVQLExtension/Resources/ and reload the QuickLook preview.

Star history

License

MIT — see LICENSE.