Pure Swift · Native on macOS

Your Mac still can’t read Markdown.Now it can.

Double-click any .md and it opens beautifully rendered — not as raw symbols in TextEdit. One click to edit, ⌘S to save. The whole app is under 5 MB, fully offline, and respectful of your Mac.

Under 5 MB · pure Swift
US$3.99 one-time
Fully offline · no tracking
TronDown
Toggle editing
E
Save
S
Data collected
0 · fully offline
Full support
CommonMark
Made for the .md files you already have
  • ChatGPT & Claude exports
  • GitHub READMEs
  • AI coding-tool output
  • Docs from your team
  • Notes & drafts
Everything included

Markdown, kept simple and pleasant

Reviewing notes, reading documentation, or writing your next draft — every feature is built for “open it, use it, get on with your day.”

Clean, distraction-free reading

Beautiful rendering with full CommonMark support. Headings, lists, tables, and code blocks all feel native, so you can just read.

Full CommonMark
01

Read ⇄ edit in one click

Hit ⌘⇧E to jump into raw Markdown, save with ⌘S, and flip back to reading. No more separate reader and editor apps.

⌘⇧E / ⌘S
02

Under 5 MB, opens instantly

Pure Swift, no Electron. The entire app is smaller than a single photo, launches in a blink, and scrolls big documents smoothly.

No Electron
03

Automatic light & dark mode

Follows your system appearance with careful contrast that stays easy on the eyes — code blocks and tables tuned for both modes.

Light / Dark
04

Fully offline, zero tracking

No internet connection, no account, no analytics, no third-party SDKs, no ads. TronDown collects no data — your documents never leave your Mac.

0 data collected
05

Large files & mixed languages

Built in pure Swift for a lightweight, responsive feel. Big documents scroll smoothly, and CJK, Arabic, Hebrew, and Thai all render correctly.

CJK · RTL · Thai
06
In-app screenshots

Every screen, clean and quiet

A native macOS window with carefully tuned contrast in light and dark — this is the TronDown you will see every day.

Reading mode
01
Reading mode
Open any Markdown file and see it beautifully rendered, instantly
Editing mode
02
Editing mode
Toggle raw Markdown with ⌘⇧E, save with ⌘S, and flip back to reading
World scripts
03
World scripts
CJK, Arabic, Hebrew, Thai, and more all render correctly
Three steps

Open. Read. Done.

01

Open

Double-click any .md file or drop it onto TronDown. No setup, no waiting — beautifully rendered right away.

Drag & drop · double-click
02

Edit when you want

Press ⌘⇧E (or click the toolbar button) to switch to raw Markdown. A clean, monospaced editor for focused changes.

⌘⇧E to toggle
03

Save and keep reading

Save with ⌘S and flip back to reading mode. Files are read and written locally only — that’s the whole workflow.

⌘S · fully offline
Private by default

Your documents never leave this Mac

TronDown collects no data. No account, no cloud, no ads — because it never connects to the internet in the first place.

0
network connections — the app never goes online
0
data collected — no analytics, no tracking, no third-party SDKs
100%
of your files stay local — read and written only when you open or save
FAQ

Questions, answered

How much does TronDown cost?

US$3.99, one-time purchase. No subscription, no in-app purchases, no ads — buy it once and it is yours.

Which Macs are supported?

macOS 14.0 or later. Apple Silicon and Intel are both supported natively via a universal binary.

Why not just use TextEdit or VS Code?

TextEdit shows Markdown as raw symbols. VS Code is a full IDE — hundreds of megabytes to read one note. TronDown is under 5 MB, opens instantly, and does one thing well.

Can I set TronDown as the default app for .md files?

Yes. Right-click any .md file → Get Info → Open with → TronDown → Change All. From then on, double-clicking any Markdown file opens it rendered.

Which Markdown syntax is supported?

Full CommonMark: headings, lists, tables, code blocks, quotes, links, images, and more all render correctly.

Does TronDown collect my data?

No. TronDown is fully offline — no internet connection, no account, no analytics, no tracking, no third-party SDKs. Your documents are read and written only on your device.

Which languages are supported?

The interface is available in English, Japanese, and Traditional Chinese. For rendering, mixed-language documents with CJK, Arabic, Hebrew, Thai, and more all display correctly.

Where can I buy it?

On the Mac App Store, available worldwide. Questions or feedback: pct@1tron.ai.

Get started now

Open your next Markdown file with TronDown

US$3.99 one-time purchase — no subscription, no in-app purchases. Download it, double-click any .md, and TronDown handles the rest.

© 2026 1Tron System Co., Ltd. · Crafted in Taiwan by 1tron
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