Stack Online Tools is the ultimate all-in-one productivity and developer toolkit for Firefox. Stop switching between sites or loading multiple add-ons — access 30+ essential online tools, text utilities, and developer helpers right from your browser. Built for developers, content creators, digital marketers, SEO professionals, and everyday users, this extension speeds up workflows with fast, lightweight, and privacy-first utilities that run locally when possible. ✔ What You Get Developer & Code Utilities

JSON Formatter & Validator – instant formatting, beautification, and error checking
JSON ↔ YAML Converter
Base64 Encode/Decode
URL Encode/Decode
HTML, CSS & JS Minifiers
Markdown ↔ HTML Converter
Robots.txt Generator for SEO and crawler structuring
Epoch Unix Timestamp
JWT Encoder/Decoder
Hash Generator
QR Code Generator
Diff Checker
Color Converter
CSS Unit Converter

These tools make Stack Online Tools a top choice for developer tools, programmer utilities, and code formatters in Firefox. Text & Content Utilities

Case Converter (uppercase, lower, title, camel, snake, kebab)
Word & Character Counter
URL Slug Generator
Line Counter & List Randomizer
Text Repeater
Text Reverser
Remove Duplicate Lines
Lorem Ipsum Generator

Essential for writers, bloggers, SEO editors, and anyone optimizing content. Security & Password Tools

Strong Password Generator (custom options)
Password Strength Checker

Perfect for web developers, admins, and safe credential creation. Image & File Tools

PNG ↔ JPG Converter
PDF ↔ JPG Converter (secure web tool)

Quick Calculators & Generators

Age Calculator
Percentage Calculator
Random Name Generator
Random Address Generator

Key Benefits ✔ All-in-one productivity tools & utilities ✔ Fast, lightweight, and user-friendly ✔ Privacy-first — tools run locally ✔ No account, registration, or tracking ✔ Replaces multiple single-purpose add-ons Stack Online Tools supports nearly every common workflow, from text conversions and data formatting to developer operations, making it one of the most versatile Firefox add-ons available. Who This Is For

Developers & engineers
SEO specialists & marketers
Writers & editors
Designers & web admins
Students & everyday users