Firefox Browser Add-ons
  • Extensions
  • Themes
    • for Firefox
    • Dictionaries & Language Packs
    • Other Browser Sites
    • Add-ons for Android
Log in
Preview of Source Code Viewer — HTML, CSS, JS, JSON & XML

Source Code Viewer — HTML, CSS, JS, JSON & XML by Nicolas Dos Santos

View & format source code with syntax highlighting — HTML, CSS, JavaScript, JSON & XML. A clean source code viewer & formatter.

0 (0 reviews)0 (0 reviews)
6 Users6 Users
Download Firefox and get the extension
Download file

Extension Metadata

Screenshots
Syntax highlighted HTML/JS/CSS/JSON/XMLAuto FormattingLine wrappingMultiple themesURLs clickableCode folding
About this extension
Tired of staring at your browser's bland, unstyled source viewer? Source Code Viewer is here to fix that. View — and format — the source of any web page with proper formatting and beautiful syntax highlighting, right from the "View Page Source" context menu or with a single click on the toolbar icon. No more walls of unreadable text. Just clean, colorized code, the way it should be.

✨ What you get:
• Beautiful syntax highlighting for HTML, CSS, JavaScript, JSON & XML
• Automatic formatting & beautification — pretty-print minified CSS, JS, JSON & HTML
• Automatic in-place formatting when you open a raw CSS/JS/JSON/XML file directly
• A range of light & dark themes
• Word wrap, line numbers & code folding
• Clickable links to jump between resources without leaving the viewer
• One-click switch back to the browser's native source view
• Available in multiple languages

Great for developers, web designers, and anyone who needs to view or format HTML, CSS, JavaScript, JSON, or XML source code — a clean source code viewer, JSON/XML viewer, and code formatter in one.
Rated 0 by 0 reviewers
Log in to rate this extension
There are no ratings yet

Star rating saved

5
0
4
0
3
0
2
0
1
0
No reviews yet
Permissions and data

Required permissions:

  • Access browser tabs
  • Access your data for all web sites

Optional permissions:

  • Access your data for all web sites

Data collection:

  • The developer says this extension doesn't require data collection.
Learn more
More information
Add-on Links
  • Homepage
  • Support site
  • Copy add-on ID
Version
1.6.1
Size
481.28 kB
Last updated
2 days ago (22 Jul 2026)
Related Categories
  • Web Development
Licence
GNU General Public Licence v3.0 only
Version History
  • See all versions
Add to collection
Report this add-on
Go to Mozilla's homepage

Add-ons

  • About
  • Firefox Add-ons Blog
  • Extension Workshop
  • Developer Hub
  • Developer Policies
  • Community Blog
  • Forum
  • Report a bug
  • Review Guide

Download

  • Download Firefox
  • Windows
  • macOS
  • iOS
  • Android
  • Linux
  • All

Latest Builds

  • Nightly
  • Beta

Firefox for Business

  • Enterprise

Community

  • Connect
  • Contribute
  • Developer

Follow

  • Instagram
  • YouTube
  • TikTok
  • Bluesky
  • Podcast
  • Privacy
  • Cookies
  • Legal

Except where otherwise noted, content on this site is licensed under the Creative Commons Attribution Share-Alike Licence v3.0 or any later version.