01 / Rendr for macOS

Markdown, rendered natively.

Keep the editor you already use. Rendr follows every save and turns the same local file into a focused AppKit preview, with no account and no remote renderer.

Platform: macOS 26 or newer
Architecture: Apple silicon
Workflow: Editor companion

Rendr image titled A complete preview workflow, showing the document outline beside a Markdown alert, table, task list, and tip. — Outline, tables, alerts, tasks, code, search, and zoom stay together in one native window. View full size. View full size.

02 / Workflow

Keep writing where you already write

Your editor stays yours

Open Markdown from Finder, Open With, the Open panel, or open -a Rendr. Keep writing in your preferred editor while Rendr refreshes the preview in place after every save.

Open the whole source in any configured editor. Direct editor presets can return to a trusted heading, fenced code block, or diagram; Xcode uses native document handoff, and Copy Source Location remains available.

A native reading space

The heading outline, Command-F search, Back and Forward history, zoom controls, and remembered reading position keep long documents easy to navigate.

Presentation Mode moves the document into a focused full-screen view with larger type and keyboard heading navigation, then restores the previous window and reading position when you leave it.

Rendr image titled Write anywhere. Preview instantly, showing a live Markdown preview beside Behavior preferences for choosing a source editor. — Edit in your preferred app while Rendr follows every save. View full size. View full size.

Rendr image titled Presentation Mode, made for reading, showing a focused full-screen document with larger typography. — Presentation Mode removes distractions and enlarges the reading view. View full size. View full size.

03 / Rendering

Markdown with room to breathe

Structure stays familiar

GitHub-flavored Markdown includes tables, task lists, strikethrough, autolinks, footnotes, heading anchors, alerts, and sanitised inline HTML. Fenced code receives syntax highlighting, line wrapping and numbering options, plus a copy control.

Extended task states remain ordinary Markdown. Activate a task indicator to update only its source marker without turning Rendr into an editor or notes database.

Rendering stays on your Mac

Bundled Mermaid and KaTeX render diagrams and math without a remote service. A focused diagram viewer adds pan, zoom, source inspection, and bounded SVG or PNG export while unsupported input remains readable.

Choose GitHub, Reader, Developer, or Token themes in Light, Dark, or system-following appearance. Typography and an optional bounded local stylesheet let the same document fit the way you read.

Rendr image titled Diagrams that look right in every appearance, showing a Mermaid flowchart, KaTeX math, and a supported PlantUML diagram. — Mermaid, supported PlantUML, and KaTeX stay crisp in Light and Dark appearances. View full size. View full size.

Rendr image titled Make every document feel at home, showing Appearance preferences over matching Light and Dark document previews. — Choose the theme and typography that fit the document. View full size. View full size.

Mermaid, bundled

Flowcharts, sequence and class diagrams, state and entity relationship diagrams, Gantt charts, architecture and C4 views, mindmaps, timelines, and more render locally from the Mermaid bundled with Rendr.

A bounded PlantUML layer

plantuml and puml fences translate a deliberate local subset covering sequence, component, activity, state, class, use case, object, deployment, and timing diagrams.

It is not a full PlantUML implementation. Unsupported grammar and styling stay readable as source with a concise error.

04 / Handoff

Preview first. Share when ready.

Quick Look before launch

Select a supported Markdown file in Finder and press Space. Rendr's sandboxed Quick Look extension produces a bounded, script-free preview from only the file Finder provides, with no network entitlement.

Polished static output

Print through the macOS print panel or export paginated A4 or US Letter PDF, continuous PDF, or script-free HTML. Static diagrams and math travel with the document, while exported HTML never retains remote resources as loadable media.

Rendr image titled Preview Markdown before opening it, showing a Finder Quick Look preview of a Markdown document. — Finder Quick Look previews supported Markdown without launching Rendr. View full size. View full size.

Rendr image titled Export polished static documents, showing the native PDF export panel and Export preferences. — Choose paginated or continuous PDF, or export script-free HTML. View full size. View full size.

05 / Privacy

Local-first by design

Your document is not a service input

Rendr has no account, analytics, tracking, document upload, or remote rendering service. Mermaid and KaTeX are bundled. Your file stays local; remote images and media load only when you allow them, and exports go only to a destination you choose.

Remote images and media are blocked by default.
Remote scripts, styles, fonts, frames, and arbitrary fetches remain blocked.
Folder and editor access follows explicit, revocable macOS permissions.
Quick Look and exported HTML never load remote resources.

Rendr image titled Local-first by design, showing a document preview and Privacy preferences with remote content blocked by default. — Accounts, analytics, and remote rendering are outside the product boundary. View full size. View full size.

Read the complete Rendr Privacy Policy.

06 / Support

Questions or feedback?

rendr-support@rhau.se

Use this address for help, feedback, privacy questions, and feature suggestions. Rendr opens a blank, user-initiated message and never attaches documents or diagnostics.

Helpful details

Your Rendr version.
Your macOS version.
Short, reproducible steps.
The smallest safe sample you choose to share, when one is needed.

Please do not send private documents, credentials, full local paths, logs, or automatic diagnostic collections.