Lightweight Markdown editor on your browser

markdown-os lets you visualize and edit markdown files in your browser, with more features than built-in IDE preview

View on GitHub

Markdown-OS editor with Contents sidebar, WYSIWYG preview, code block, table, and Mermaid diagram

Built for developers

View and edit AI-generated .md files easily

graph TD A[CLI] --> B[Server] B --> C[Browser] C --> D[Editor]

Visualize Mermaid Diagrams

Embed flowcharts, sequence diagrams, and more. Rendered live and easy to visualize with zoom and pan tools that are not available in basic IDE preview.

Set up FastAPI server

Write markdown parser

Add WebSocket sync

Deploy to production

Interactive task lists

Clickable checkboxes for task lists that work as you'd expect. Check items off directly in the editor without touching the raw markdown.

main.py

1from fastapi import FastAPI

3app = FastAPI()

5@app.get("/")

6def read_root():

7 return {"hello": "world"}

Syntax highlighting

Code blocks with full syntax highlighting for 100+ languages. Every block includes a copy button, language label, and optional line numbers.

Quick Start

Installation

Features

WYSIWYG Editor

Automatic Table of Contents

Auto-generated from your headings. Nested structure mirrors your document hierarchy with smooth scrolling navigation.

README.md

setup.md

notes.md

▼ docs/

▼ guides/

◼ setup.md

◼ notes.md

◼ README.md

File tree & workspace

Open entire directories at once. Browse with the file tree sidebar, search for files, and switch between up to 15 open tabs.

Theme

Color themes

Six built-in themes including Dracula, Nord Light, Nord Dark, and Lofi. Switch with one click to match your preferences.