Firefox Browser Add-ons
  • Extensions
  • Themes
    • for Firefox
    • Dictionaries & Language Packs
    • Other Browser Sites
    • Add-ons for Android
Log in
Preview of ZeroWebTools - Developer Utilities

ZeroWebTools - Developer Utilities by Zeeshan Ahmad

Free offline developer utilities: JSON tree formatter, side-by-side diff checker, JWT decoder, Base64 cipher, and URL percent encoder.

0 (0 reviews)0 (0 reviews)
Download Firefox and get the extension
Download file

Extension Metadata

About this extension
ZeroWebTools is a lightweight, 100% offline developer toolbelt right in your Firefox toolbar.

All data transformations and formats are executed locally in your browser context using WebAssembly and client-side JavaScript. No data is ever sent to external servers, making it a safe choice for corporate developers handling sensitive API credentials, production logs, tokens, or proprietary code blocks.

🚀 Six Essential Offline Utilities in One Popup:
  1. JSON Formatter & Tree Explorer: Paste raw JSON to validate it, pretty-print it (with collapsible arrays and objects), or minify it instantly.
  2. Side-by-Side Diff Checker: Compare two blocks of code or text files inline to highlight additions, deletions, and line-level changes.
  3. JWT Debugger & Decoder: Instantly inspect JSON Web Tokens. Decode headers, payload claims, and signatures securely offline.
  4. Case Converter: Transform naming conventions between camelCase, snake_case, kebab-case, and PascalCase.
  5. Base64 Cipher: Encode strings to Base64 or decode hashes back to readable plain text.
  6. URL Encoder/Decoder: Clean percent-encoding from URL parameter strings and format query parameters.

🔒 Privacy-First Design:
  • Runs completely offline in your browser's sandbox memory.
  • Zero telemetry, tracking scripts, or analytical cookies.
  • Zero server communication.

Check out our full catalog of 43+ free client-side tools (including PDF compilers, HEIC photo converters, and financial models) at:
👉 https://zerowebtools.com/
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

Data collection:

  • The developer says this extension doesn't require data collection.
Learn more
More information
Add-on Links
  • Support site
  • Support Email
  • Copy add-on ID
Version
0.1.0
Size
30.07 kB
Last updated
5 days ago (28 May 2026)
Related Categories
  • Web Development
  • Privacy & Security
Licence
MIT Licence
Privacy Policy
Read the privacy policy for this add-on
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

Browsers

  • Desktop
  • Mobile
  • Enterprise

Products

  • Browsers
  • VPN
  • Relay
  • Monitor
  • Pocket
  • Bluesky (@firefox.com)
  • Instagram (Firefox)
  • YouTube (firefoxchannel)
  • 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.