LeanMark Releases

A focused Markdown viewer for desktop

Open the README,
not the IDE.

Read GitHub-flavored Markdown and Mermaid diagrams offline in thin native hosts for Windows, Linux, and macOS.

View platform downloads View source

v0.2.0 · 3 desktop platforms · MIT licensed

Signing status: Windows is unsigned. The macOS preview is ad-hoc signed but not notarized. Platform notes accompany every artifact.

LeanMark displaying a local Markdown document with a Mermaid flowchart and document outline.
A real local document rendered by LeanMark.
3
Native desktop platforms
~321 ms
Windows baseline: native window visible
~163 MiB
Windows baseline: full-process peak private memory
MIT
Free to use, inspect, and improve

The reading workflow

A document opens as a document.

LeanMark turns a Markdown file into a calm reading surface without project indexing, editor panes, extensions, or workspace management.

  • CommonMark plus GFM tables, tasks, autolinks, and strikethrough
  • Automatic outline, find, zoom, print, themes, and reading progress
  • Relative local images and Markdown links
  • Live refresh after the file changes on disk
architecture.md local file 
# Release path

The viewer stays focused on
the current document.

```mermaid
flowchart LR
  File --> Parse --> Read
```
LeanMark rendering flow A Markdown file is parsed by MD4C, shown in a trusted local view, and diagrams are rendered by the bundled Mermaid library only when needed. Markdown local file MD4C raw HTML off Reader trusted view Mermaid only when present

Offline diagrams

Mermaid stays with the document.

The release includes its Mermaid renderer. Diagrams work without an active connection, and the library is loaded only when the document contains a Mermaid fence.

LeanMark is explicit about its architecture: one portable C++ parser feeds native Win32, GTK, and AppKit hosts. Each host uses the operating system web runtime for selectable text, printing, images, and diagrams.

Measured, not magical

Small package. Honest runtime cost.

System web runtimes stay outside LeanMark's packages, but renderer, GPU, and utility processes still use memory. Package size is not the same as total footprint.

The published figures below are a Windows 11/WebView2 baseline. Hardware, system state, runtime version, and document complexity affect results; Linux and macOS measurements are not inferred.

Read the measurement method
4.11 MiB
Windows staged application payload
320.88 ms
Windows native window visible, simple document
162.94 MiB
Windows peak private memory, full app tree

Practical guards

Local Markdown is treated as untrusted input.

LeanMark narrows what a document can do, then verifies those boundaries against hostile fixtures.

Read the security policy
  • Raw HTML disabledMD4C renders Markdown without activating embedded HTML.
  • Strict local page policyA Content Security Policy limits scripts and resources.
  • Remote content blockedRemote images, downloads, popups, and permissions are denied.
  • External links leave the readerHTTP, HTTPS, and mail links go to the operating-system handler only after a click.

Platform releases

Native packages for three desktops.

GitHub Releases provides a Windows x64 ZIP, an Ubuntu 24.04 / Debian-compatible x86-64 package, and one Universal 2 macOS preview for Intel and Apple silicon.

Transparent trust status. Windows may show an unknown-publisher warning. The macOS preview is ad-hoc signed and not notarized. Each package has a SHA-256 sidecar that verifies a byte-for-byte match; it does not establish publisher identity. The release notes document platform requirements.
View v0.2.0 downloads Release notes

Windows x64 · Ubuntu 24.04 / Debian-compatible x86-64 · macOS Universal 2 preview

  1. 01
    Windows x64

    Portable ZIP with optional per-user Default Apps integration.

  2. 02
    Linux x86-64

    Debian package with declared GTK 4 and WebKitGTK 6.0 dependencies.

  3. 03
    macOS universal preview

    One AppKit bundle for Intel and Apple silicon, ad-hoc signed and not notarized.

Built in public

Useful tools get better through real documents.

LeanMark is early, public, and MIT licensed. Compatibility reports based on real, non-private Markdown documents are welcome, especially documents containing Mermaid diagrams.

Report an issue View roadmap