Renders as you type · Edit any line

Markdown that
becomes the page.

A gorgeous WYSIWYG markdown editor that renders the marks away as you type — native, private, and ruthless about leaving your files alone.

Pricing →

Power, when you reach for it

Not just a pretty editor.

…and a hundred small things

The whole point

Your bytes are sacred.

Plain text is the document — the pretty view is only a projection over it. Fix one line and git diff shows exactly one line. Constly never reformats, re-wraps, or “normalizes” the markdown you didn't touch — a one-word change stays a one-word change, not a whole-file reflow.

What's inside

Everything you reach for, already here.

  1. 01

    Live preview that gets out of your way

    Write **bold** and the asterisks melt away the moment your cursor leaves — click back in and they return, in place, no flicker. Headings, lists, code, links, quotes: markdown that reads like prose and shows its source only where you're working.

  2. 02

    Write the way you think

    Focus mode dims everything but the sentence you're in. Typewriter mode keeps the line centered. Real modal Vim with a status bar when you want it. And a command palette (⌘⇧P) plus quick-open (⌘P) so every action is one fuzzy search away.

  3. 03

    Tables you can actually edit

    A markdown table renders as a real grid — click a cell and type, Tab across, Enter for the next row. Leave it and the source reflows to clean, aligned pipes by itself. Toggle the grid off if you'd rather see raw markdown.

  4. 04

    Math, diagrams, footnotes

    KaTeX for $inline$ and display math, Mermaid diagrams from a fenced block, footnotes and an in-document [toc] — each rendered privately, and each showing its source instead of crashing when something's off.

  5. 05

    Private by default

    No accounts, no telemetry, nothing phoning home. Remote images don't load until you say so — most editors fetch them the instant you open a file, quietly handing your IP to whoever's hosting. Your document stays on your machine.

  6. 06

    Local version history

    Off by default. Turn it on and Constly snapshots each document as you save, shows the history from the title bar, and lets you diff any past version against now and restore it — undoably. Local-only, never uploaded, with a disk cap and a never-snapshot list.

  7. 07

    Leaves home cleanly

    Its own bundled typeface, so a document reads the same on every machine. Light, Sepia, and Dark themes. And when a draft is done: export to a self-contained HTML page, PDF, Word, ODT, RTF, LaTeX, or EPUB — or just copy it as rich text.

  8. 08

    Native feel, tiny footprint

    A Rust core and a real native window — instant cold start, and an installer a fraction of the usual Electron heft. Tabs, workspace search, and session restore are built in, not bolted on. It opens exactly where you left it.

Pricing

Free until your conscience kicks in.

The WinRAR deal
Free for as long as you need

Every feature works — no expiry, no watermark, no locked exports. After two weeks a polite dialog says hello about once a week. That's the whole nudge. Keep using it free until it's earned its keep.

  • The full app, free to use
  • Never expires — ever
  • A gentle weekly reminder after 14 days
  • Pay if and when you've made it
Download for macOS

No account, no card — ever.

Buy once
$19.99once
in USD · plus applicable tax

Make the dialog go away for good and back a tiny studio. One-time — no subscription, no upsell. Your license covers every platform Constly ships on, with free updates within the version.

  • One-time purchase, no subscription
  • macOS today — Windows & Linux coming soon
  • Free updates throughout the version
  • 14-day refund, no questions asked

Buying for a team? Email us about volume licenses.

Questions

The honest answers.

Will it mangle my files?
No. Plain text is the document; the pretty view is just a projection over it. Constly never re-wraps, reorders, or “normalizes” markdown you didn't touch — editing one paragraph rewrites that paragraph and nothing else. Your CRLFs, your BOM, your trailing spaces all survive. Verified on a real-world corpus every release.
What's the catch with “free”?
There isn't one hiding in the features. Every capability works forever, paid or not. The app never expires, and exports never carry a watermark. After two weeks a polite dialog appears asking you to buy. That dialog is the entire business model.
How much does Constly cost?
Nothing to start. Constly is free to use on macOS — every feature unlocked, no expiry, no watermark. If you'd like to support it and retire the gentle weekly reminder, a one-time license is $19.99 (USD). No subscription, ever.
Which platforms?
macOS, Windows, and Linux — each a real native build, not the same web page in three wrappers. macOS ships today; Windows and Linux are on the way.
How do I install Constly?
Download the disk image from constly.com/download, open it, and drag Constly to your Applications folder. It's signed and notarized by Apple, universal (Apple Silicon and Intel), and needs macOS 11 or later.
Does it work offline?
Entirely. There's no account to create and no server to reach. Constly never needs the network to open, edit, or save a file.
What can it export?
A self-contained HTML page (math, diagrams, highlighted code and images all baked in), PDF, Word, ODT, RTF, LaTeX, and EPUB — plus “copy as rich text” for pasting into Mail, Word, or Slack with formatting intact.
Can I get a refund?
Yes — within 14 days, no questions asked.