Mardo

Native macOS · Private beta

Markdown at any size.
Still just a file.

Mardo is the native Mac editor for serious Markdown in the AI age. Faster than Typora. Instant at any size. Full CommonMark. Every source byte survives.

Sign up for the private beta → Read the release contract ↓

No vapor-builds. The first private beta stays in the lab until every promise on this page clears its release gate.

The visual joke automatically types a tiny marketing document, then Mardo immediately opens a 50 gigabyte Markdown file.

YES, THE TYPING IS AUTOMATIC

It was important that you know we can also make letters appear one at a time.

Local files Bounded memory Native rendering No AI inside No document upload

The private beta contract

Six promises.
No asterisks hiding the architecture.

Mardo is being finished against release gates, not a feature-shaped mood board. The build does not go out until these claims are real on the same app people receive.

01 · SCALE

Instant at any size.

Mardo maps the file and renders the viewport. Opening a document does not require copying the whole thing into an editor-shaped pile of memory.

50 GBsame bounded document description
Release gate: open, seek, edit, and save under fixed time and memory budgets.
02 · SPEED

Faster than Typora.

Not “feels snappy.” Same Mac. Same files. Same cold and warm cases. The comparison is a measured shipping gate.

Typora→Mardoalready open
Typora is the comparison, not the design authority.
03 · LANGUAGE

Full CommonMark.

The pinned CommonMark 0.31.2 corpus, named GFM extensions, and explicit Mardo additions share one source-ranged grammar.

652normative CommonMark examples
Tables, tasks, footnotes, autolinks, math, Mermaid, callouts, highlights, and safe literal fallback.
04 · OWNERSHIP

Every byte stays on the table.

If Mardo cannot render a construct richly, it shows the source honestly. It never makes unfamiliar bytes disappear just to keep the canvas pretty.

<vendor:block mode="odd">
  bytes Mardo did not invent
</vendor:block>
Display is lossless. Save is lossless. Your file remains your file.
05 · COEXISTENCE

External edits are a normal case.

Git, an agent, a formatter, and another editor can all touch the file. Mardo detects replacement and conflict instead of silently overwriting newer work.

disk changed→compare→reload or resolve
Safe from external edits means no quiet data loss.
06 · OUTPUT

Deterministic PDF.

A fixed document snapshot produces fixed pagination and drawing order through Mardo’s own bounded export path.

Same input. Same policy. Same pages. Proved across the release corpus.

This is the actual app

A Mac editor.
Not a browser in a trench coat.

Mardo uses native macOS windows, text input, file coordination, menus, Quick Look, accessibility, and PDF plumbing. The portable parser and rendering policy stay outside AppKit, where they can remain deterministic and testable.

  • ✓ Rich editing that reveals the exact Markdown at the caret
  • ✓ Outline, find and replace, word and token counts
  • ✓ Native tables, task lists, code, math, and diagrams
  • ✓ Finder Quick Look without launching the editor
  • ✓ Light and dark surfaces made for long sessions
The real Mardo macOS app displaying headings, tasks, links, a table, code, math, Mermaid, footnotes, callouts, and an image in one rich Markdown document.
REAL MARDO WINDOW

One document exercising the rich block surface. No website reconstruction.

Serious Markdown

Everything expected.
The architecture others avoid.

AI can produce a novel-sized Markdown file before lunch. Mardo does not need AI inside the editor. It needs to open the result, preserve it, and get out of the way.

#

Readable by default

Headings, lists, quotes, links, images, code, thematic breaks, and the entire CommonMark baseline.

▦

GitHub-shaped work

Tables, task lists, strikethrough, autolinks, footnotes, and the extensions common in repositories and agent output.

∑

Technical documents

Fenced languages, native syntax highlighting, inline and display math, Mermaid diagrams, callouts, and highlights.

{ }

Unknown stays known

Raw or unfamiliar syntax remains visible as source. Unsupported never means silently discarded.

Deliberately not AI-powered

AI made the Markdown.
Mardo keeps it yours.

No prompt box. No document upload. No account-shaped excuse to hold your files. Mardo is serious infrastructure for reading and editing the artifacts AI leaves behind.

DOCUMENT PATH ~/work/agent-evidence.md local · ordinary · yours

Private beta

Bring the file that breaks everybody else.

Sign up and Mardo will email your private beta page immediately. Your place is reserved now; the same page becomes the signed-build download when the release contract clears.