Here are a few selected applications and extensions that will allow you to view and debug JSON documents in a desktop application like Notepad++ or inside a web browser.
Extension
Set any custom image as favicon to a JavaScript bookmarklet in Mozilla Firefox with Bookmark Favicon Changer add-on. It’s a free extension, and works will all flavours of Firefox.
Markdown Here is an extension that lets you write email in Markdown and render it before sending with syntax highlighting. It’s available for Google Chrome, Mozilla Firefox, and Thunderbird.
Facebook Fast Delete Messages extension simplifies Facebook message deletion task to a simple one-click process. It also lets you bulk delete all messages.
Scriptify is a light weight extension for Firefox that provides a hassle-free way to convert any user script to a standalone add-on for Firefox.
Plus it later is a Chrome extension that allows users to save Google Plus postings to their Read it Later account and read them later at their convenience
Scratchpad is a free, fast, and lightweight note-taking application for Google Chrome with local saving and Google Docs synchronization feature.
Customize the new Google drop-down menu by reordering various services and products with Big G Drop Down Sorter extension for Chrome browser
Hide or remove the new real time feed ticker in Facebook from your homepage and sidebar on Chrome and Firefox, and disable the floating top bar on Chrome.
Pillarbox is a Google Chrome application that gives you a full screen, distraction free writing environment right within your browser.