Online Markdown Viewer with HTML Preview by mdapp leadtech
Useful Online Markdown Viewer with HTML Preview to view markdown online, preview web pages without clutter, and open .md or .json files.
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About this extension
Online Markdown Viewer removes ads, sidebars, and clutter while preserving headings, lists, tables, links, and clean, readable structure. Use it to extract full articles, selected text, and AI chats, and to capture YouTube transcripts into a cleaner format. Open this online markdown viewer from the toolbar or right-click menu and load the result in a convenient browser sidebar. It works with full pages, selected parts of a page, local .md and .json files, and structured reading workflows, with Mermaid and KaTeX support for technical content.
🔹 Key Features
📝 Web page to GitHub Flavored Markdown conversion
📐 KaTeX math rendering and Mermaid diagram support
🤖 AI chat extraction for supported assistants
🗂️ Table of Contents with section filtering checkboxes
🖥️ HTML preview with source view
📄 Open .md and .json files in a structured view
🎨 Syntax highlighting, code copy buttons, and dark mode
💾 Export options: copy, save .md, save .htm, and print to PDF
🔎 Search with counter, navigation, and zoom controls
🔹 Clean reading for the web
Our Online Markdown Viewer with HTML Preview is built to make busy sites easier to use:
🔺 remove banners, menus, and clutter
🔺 keep titles, code blocks, tables, and links intact
🔺 make articles, guides, and notes easier to scan or navigate with TOC
🔺 focus on the main text instead of heavy layout
🔹 HTML preview when you want a rendered view
Switch between markdown view and HTML preview as needed.
➤ open an entire web page in your browser
➤ convert only a selected part
➤ read the result as markdown
➤ preview the rendered version in clean HTML before saving or printing
That makes the extension useful when you want both a markdown viewer and a practical markdown to html workflow in one place.
🔹 AI chat extraction
Online Markdown Viewer helps turn long AI conversations into cleaner, reusable text from these currently supported chats:
📌 extract chats from ChatGPT
📌 extract chats from Claude
📌 extract chats from Gemini
📌 extract chats from Copilot
📌 extract chats from Grok
It is useful for saving prompts, answers, notes, and research conversations in a more readable format for reuse, printing, or export.
🔹 Built for structured and technical material
This Online Markdown Viewer extension supports features that are especially useful on more advanced documents:
🧩 Mermaid light support for diagrams
🧩 KaTeX support for math notation
🧩 GitHub-style document rendering
🧩 better readability for technical documentation and other structured text
🔹 Open files and read them in the browser
The extension also works well with local files and browser-based reading:
📂 open .md files from your computer
📂 open .json files from your computer in a structured view
📂 convert html files opened in your browser into a markdown view in the sidebar
📂 use search and Table of Contents (TOC) checkboxes to select sections for copy, print, or save
🔹 Save output the way you need it
Different tasks call for different formats. You can:
💾copy markdown or selected TOC sections to the clipboard
💾 copy rendered HTML
💾 save as .md or .htm
💾 print directly or save as PDF using browser or operating system print options.
This is useful for research notes, documentation, reference material, study content, and offline reading in Firefox.
🔹 Useful for transcript, chat, and productivity workflows
Some material is harder to reuse in its original form. This Online Markdown Viewer helps by letting you:
📌 capture YouTube transcripts when they are available on the page
📌 save transcript output with timestamp and source references
📌 capture selected AI chat text from the right-click menu
📌 reuse converted content in Obsidian or Notion markdown flows
📌 keep consistent formatting across notes and projects
📌 convert html pages to md files for use in tools such as Jupyter notebooks or GitHub Gist pages.
It gives you a simple html to markdown workflow for turning cluttered pages into reusable text.
🔹 Privacy-friendly and lightweight
✅ no tracking of browsing activity
✅ no account required
✅ works directly in your browser
✅ focused permissions for local use and export workflows
Online Markdown Viewer with HTML Preview is a practical markdown viewer extension for viewing, extracting, previewing, printing, and saving clean text from web pages and local .md and .json files directly in Firefox.
🔹 Key Features
📝 Web page to GitHub Flavored Markdown conversion
📐 KaTeX math rendering and Mermaid diagram support
🤖 AI chat extraction for supported assistants
🗂️ Table of Contents with section filtering checkboxes
🖥️ HTML preview with source view
📄 Open .md and .json files in a structured view
🎨 Syntax highlighting, code copy buttons, and dark mode
💾 Export options: copy, save .md, save .htm, and print to PDF
🔎 Search with counter, navigation, and zoom controls
🔹 Clean reading for the web
Our Online Markdown Viewer with HTML Preview is built to make busy sites easier to use:
🔺 remove banners, menus, and clutter
🔺 keep titles, code blocks, tables, and links intact
🔺 make articles, guides, and notes easier to scan or navigate with TOC
🔺 focus on the main text instead of heavy layout
🔹 HTML preview when you want a rendered view
Switch between markdown view and HTML preview as needed.
➤ open an entire web page in your browser
➤ convert only a selected part
➤ read the result as markdown
➤ preview the rendered version in clean HTML before saving or printing
That makes the extension useful when you want both a markdown viewer and a practical markdown to html workflow in one place.
🔹 AI chat extraction
Online Markdown Viewer helps turn long AI conversations into cleaner, reusable text from these currently supported chats:
📌 extract chats from ChatGPT
📌 extract chats from Claude
📌 extract chats from Gemini
📌 extract chats from Copilot
📌 extract chats from Grok
It is useful for saving prompts, answers, notes, and research conversations in a more readable format for reuse, printing, or export.
🔹 Built for structured and technical material
This Online Markdown Viewer extension supports features that are especially useful on more advanced documents:
🧩 Mermaid light support for diagrams
🧩 KaTeX support for math notation
🧩 GitHub-style document rendering
🧩 better readability for technical documentation and other structured text
🔹 Open files and read them in the browser
The extension also works well with local files and browser-based reading:
📂 open .md files from your computer
📂 open .json files from your computer in a structured view
📂 convert html files opened in your browser into a markdown view in the sidebar
📂 use search and Table of Contents (TOC) checkboxes to select sections for copy, print, or save
🔹 Save output the way you need it
Different tasks call for different formats. You can:
💾copy markdown or selected TOC sections to the clipboard
💾 copy rendered HTML
💾 save as .md or .htm
💾 print directly or save as PDF using browser or operating system print options.
This is useful for research notes, documentation, reference material, study content, and offline reading in Firefox.
🔹 Useful for transcript, chat, and productivity workflows
Some material is harder to reuse in its original form. This Online Markdown Viewer helps by letting you:
📌 capture YouTube transcripts when they are available on the page
📌 save transcript output with timestamp and source references
📌 capture selected AI chat text from the right-click menu
📌 reuse converted content in Obsidian or Notion markdown flows
📌 keep consistent formatting across notes and projects
📌 convert html pages to md files for use in tools such as Jupyter notebooks or GitHub Gist pages.
It gives you a simple html to markdown workflow for turning cluttered pages into reusable text.
🔹 Privacy-friendly and lightweight
✅ no tracking of browsing activity
✅ no account required
✅ works directly in your browser
✅ focused permissions for local use and export workflows
Online Markdown Viewer with HTML Preview is a practical markdown viewer extension for viewing, extracting, previewing, printing, and saving clean text from web pages and local .md and .json files directly in Firefox.
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Permissions and data
Required permissions:
- Input data to the clipboard
- Download files and read and modify the browser’s download history
Data collection:
- The developer says this extension doesn't require data collection.
More information
- Add-on Links
- Version
- 2.3.1
- Size
- 1.17 MB
- Last updated
- 9 hours ago (Mar 23, 2026)
- Related Categories
- License
- Mozilla Public License 2.0
- Privacy Policy
- Read the privacy policy for this add-on
- Version History
- Add to collection