PeekPlain
Every file, plainly.
Markdown, PDFs, images, code and data in one fast Mac app. Nothing hidden, nothing damaged.
Free beta for macOS 15 and later. Early days: Markdown and code come first, the rest is on its way (see the list below).
Quick Look
Space bar. Done.
Select a Markdown, JSON, CSV or code file in Finder and press Space. You see it rendered, not as a wall of symbols. Finder thumbnails get real previews too.
The Quick Look extension runs without scripts and without a network.
For AI-written files
Built for AI's paper trail
Claude, ChatGPT and Cursor leave plans, notes and logs as Markdown. Keep them open while they write: PeekPlain reloads when the file changes, keeps your scroll position and shows an "Updated just now" pill.
It reads the file. It does not watch anything else on your Mac.
Command palette
Everything is one ⌘K away
Every action in PeekPlain is a command with a name. Press ⌘K, type a few letters, press Return. ⌘P jumps to any file in the folder. Menus, the toolbar and the palette all list the same commands, so nothing is hidden behind an unlabeled icon.
Safe saving
Never damages your files
When you save a change, PeekPlain writes a copy first, reopens it to check it is sound, keeps a backup of your original, and only then swaps it in. If the check fails, your file is untouched and you are told.
It cannot recover a file that was already damaged before you opened it. It does promise not to be the one that damages it.
quarterly-report.pdf
- Reopened and checked after saving
- Original kept as a backup
- Restore any earlier version from the File menu
Formats
Opens everything, in order
PeekPlain is being built one format at a time. Here is where each one stands today, with no rounding up.
Markdown
GitHub tables, task lists, callouts, math, diagrams, front matter, outline, five themes.
Available nowText and code
Syntax colors, line numbers, wrap toggle, quick on big files.
Available nowQuick Look and thumbnails
Markdown, JSON, CSV and code in Finder.
Available nowJSON, YAML, CSV
Collapsible trees, fast tables, validation errors with line numbers.
In progressViewing, annotations with verified saving, page tools. OCR and compression in Pro.
In progressImages
Folder browsing, Live Text, basic edits, batch tools in Pro.
In progressHTML, video, audio
HTML with scripts off by default. Playback with frame step and speed.
In progressArchives, fonts, 3D
Look inside a ZIP, browse glyphs, orbit a USDZ model.
LaterPreview vs PeekPlain
An honest comparison
Preview comes with your Mac, it is free, and it is good at images and basic PDFs. Here is where PeekPlain is meant to be better, and where it isn't yet.
| Preview | PeekPlain | |
|---|---|---|
| Renders Markdown | No | Yes, available now |
| Reloads when a file changes | No | Yes, keeps your place |
| Syntax-colored code | No | Yes, available now |
| Verified saves with a backup | Not promised | Yes, for edits PeekPlain makes |
| Command palette and CLI | No | Palette now, CLI in Pro |
| Make scanned PDFs searchable, compress, merge and split | Limited | In Pro, arriving with 1.0 |
| Images, PDFs and signatures | Yes, mature | Arriving through 2026. Keep Preview until then |
| Price | Free | Free, Pro $24 once |
Pricing
Free, or $24 once
No subscription, no account. Pro is for heavy PDF and image work and for power users.
Free
Forever.
- All viewing, tabs and folder browsing
- Three Markdown themes
- Quick Look and Finder thumbnails
- The ⌘K command palette
- Basic PDF and image tools
Pro
Once. Includes one year of updates. Launch price $19.
- OCR, PDF compression, merge and split
- Batch image tools and color adjustments
- Command-line tool and Shortcuts actions
- On-device AI summaries on macOS 26
- Folder search, compare view, edit mode
Pro starts with a 14-day trial. Pro features are switched on during the free beta.
Questions
Does it send my files anywhere?
No. PeekPlain works offline. Previews load nothing from the network, and the on-device AI features run on your Mac. See the privacy page.
Will it replace Preview?
Only if you want it to. You can set PeekPlain as the default for Markdown, text and code files first, and add PDFs and images when those modules are ready.
What happens when the Pro trial ends?
Everything in Free keeps working. Pro features show an upgrade screen once per session. No nagging, no locked files.
If I stop paying for updates, do I lose the app?
There is nothing to stop paying. Pro is one payment and includes a year of updates. After that you keep your version forever, or renew updates for about $12 a year.
Which Macs does it run on?
macOS 15 and later. On-device AI needs macOS 26 with Apple Intelligence turned on, and is hidden everywhere else.
Is there a Windows or iPhone version?
No. PeekPlain is a Mac app, built to feel like part of macOS.
Can I install it with Homebrew?
Soon: brew install --cask peekplain. It also installs the peekplain command-line tool.
See it plainly.
Download the free beta, open a Markdown file, press the arrow keys.
Pro is $24, once. Not a subscription.