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Card 509 of 9982026-09-04 issue

Observed arrival · 2026-09-04

Markdown Companion reads what your AI writes

markdowncompanion.app Observed source
Editorial interest 82/100 Selection signal · not a rating of the site

A local browser extension that renders Markdown files cleanly and shows line-by-line changes as they are saved.

Landing page captured for the 2026-09-04 issue.

Field notes

The extension is designed around local Markdown folders rather than a hosted documentation workspace. Its described workflow watches a file on disk and can show a GitHub-style inline diff before reloading changes, including edits made by an editor or coding assistant. The page lists support for five Markdown-related file extensions, Mermaid diagrams, KaTeX math, folder navigation, scroll-spy outlines, and sanitized embedded HTML. It also describes light, dark, sepia, and high-contrast reading modes.

Observed signals

Read the marks

Editorial observations of this landing page, not a rating.

OpenPublic substance visible
PrettyNotable craft visible
ProPolished or operationally mature
NicheUnusually specific use

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markdowncompanion.app

Landing page observed 2026-09-04. The live site may have changed.