20 Free Browser-Based Developer Tools Every Programmer Should Bookmark.

Cetox Dev — Sun, 05 Jul 2026 08:59:21 +0000

If you're a developer, there's a good chance your browser looks something like mine.
One tab has your documentation.
Another has Stack Overflow.

Three more are open for debugging.
Then you have a JSON formatter, a UUID generator, a JWT decoder, a SQL formatter, a Base64 encoder, and somehow you've ended up with 20 tabs open just to finish a single feature.

It sounds ridiculous, but that's exactly how most of us work.
Every day we jump between different utility websites just to perform tiny tasks that take less than a minute.

Need to format JSON?
Open another website.
Need a UUID?
Another website.
Need to compare two files?
Another website.
Need to decode a JWT?
Yep... another website.

After doing this for years, I realized something.
The problem wasn't the tools.
The problem was having them scattered across dozens of different websites.
Some were overloaded with advertisements.
Some required signups. Some uploaded your data to their servers. Some looked like they hadn't been updated since 2012.
And almost every single one interrupted the actual work of building software. So I decided to build something different.

Why I Built CETOX
The original idea wasn't to build another "developer tools" website.There are already hundreds of them.
Instead, I wanted a place where I could open one bookmark and find everything I regularly use while coding.
No unnecessary complexity.
No accounts.
No premium popups every five minutes.
No waiting for servers to process simple tasks.
Most importantly, whenever possible, your data stays inside your browser.
If you're formatting JSON or decoding a JWT, there's usually no reason that information needs to leave your computer.
Modern browsers are incredibly powerful.

Why not use them?
That's how CETOX was born.

A growing collection of browser-based developer utilities designed to make everyday development faster, cleaner and more private.

What Makes Browser-Based Tools Better?
Many developers don't think about what happens after they paste sensitive information into an online tool.

Consider these examples:
API responses containing customer emails
Internal JWT tokens
Database dumps
Configuration files
SQL queries
Source code snippets

If a website processes everything on its backend, you have no idea whether your data is:
Logged
Cached
Stored
Used for analytics
Deleted immediately

With browser-based tools, much of that processing can happen locally.
That means:
Faster
More private
No waiting for uploads
No installations
No unnecessary accounts

For developers, that's a huge quality-of-life improvement.
Here Are 20 Developer Tools I Actually Use

JSON Formatter
JSON has become the language of modern APIs.
Unfortunately, production responses usually arrive as one gigantic unreadable line.
Instead of manually indenting nested objects, a formatter instantly makes everything readable.
A good formatter saves time every single day.
https://cetox.dev/json-formatter
Password Generator
Creating secure passwords shouldn't involve smashing random keys on your keyboard.
Whether you're configuring a database, creating environment variables or testing authentication, generating strong passwords takes seconds.
Being able to customize:
Length
Symbols
Numbers
Uppercase
Lowercase
makes it useful for almost every project.
https://cetox.dev/password-generator
Background Remover
This is probably my favorite addition.
Sometimes you only need to remove the background from a logo, profile photo or product image.
Opening Photoshop feels excessive.
Uploading images to random websites doesn't always feel comfortable either.
A browser-based background remover solves the problem in seconds.
Perfect for:
Landing pages
Blog thumbnails
Product images
Team photos
Startup logos
https://cetox.dev/background-remover
Regex Tester
Regular expressions are amazing.
Until they aren't.
Everyone has written a regex that looked perfect....and then matched absolutely everything except the thing it was supposed to.
Being able to test expressions against sample text while seeing matches update instantly makes debugging dramatically easier.
https://cetox.dev/regex-tester
Base64 Encoder & Decoder
If you've ever worked with APIs, authentication or embedded assets, you've probably needed Base64.
Instead of opening a terminal every time, it's much easier to encode or decode strings directly in the browser.Simple. Fast. Done.
https://cetox.dev/base64-encoder
Diff Checker
Ever spent thirty minutes trying to figure out why two configuration files behave differently? Only to discover one missing character? A diff checker highlights additions, deletions and changes immediately.
It's one of those tools you don't need every day...but when you do, it saves hours.
https://cetox.dev/diff-checker
Hash Generator
Need an SHA-256 hash? MD5? SHA-512? Instead of installing another package or writing a quick script, generating hashes directly in the browser is often the fastest solution. Great for verifying downloads and checking data integrity.
https://cetox.dev/hash-generator
SQL Formatter
ORM-generated SQL is almost impossible to read.
One click transforms a single-line query into something humans can actually understand. That alone makes debugging significantly easier.
https://cetox.dev/sql-formatter
Cron Generator

Cron expressions look simple until you actually need to write one.
Was it:
0 */6 * * *
or
*/6 * * * *
Instead of searching Google every single time, a cron generator lets you build schedules visually and immediately understand when they'll run.
Whether it's backups, reports, cache clearing, or scheduled jobs, it removes the guesswork.
https://cetox.dev/cron-generator

JWT Decoder
Every developer working with APIs has copied a JWT token at some point.
Instead of manually splitting the token or writing a script, a JWT decoder instantly shows:
Header
Payload
Claims
Expiration
It's one of those tools that makes authentication debugging dramatically easier.
https://cetox.dev/jwt-decoder
Unix Timestamp Converter
Ever seen something like:
1783359024
and wondered what date that actually represents?
Unix timestamps appear everywhere—from APIs and databases to logs and monitoring systems.

Converting them instantly saves a surprising amount of time.
https://cetox.dev/unix-timestamp

CSS Minifier
Shipping unnecessary whitespace isn't the biggest performance issue but it certainly doesn't help.
Whether you're embedding CSS into an HTML file or preparing production assets, minifying stylesheets is an easy optimization.
https://cetox.dev/css-minifier
Markdown to HTML
Documentation usually starts as Markdown. Sometimes you need HTML instead. Rather than relying on a plugin or another package, converting Markdown instantly inside the browser is much faster.
Perfect for:
Documentation
Email templates
CMS editors
Static websites
https://cetox.dev/markdown-to-html
URL Encoder & Decoder
Query strings become messy very quickly.
Encoding parameters correctly prevents broken URLs and strange bugs.
If you've ever worked with OAuth redirects or nested callback URLs, you know exactly why this tool exists.
https://cetox.dev/url-encoder
Color Contrast Checker
Accessibility shouldn't be optional.
Checking color contrast against WCAG standards takes seconds and helps ensure interfaces remain readable for everyone.
It's a small step that makes a big difference.
https://cetox.dev/color-contrast
HTML Entity Encoder
Sometimes you need to display HTML without actually rendering it.
Encoding entities prevents browsers from interpreting tags and keeps documentation, tutorials, and code examples readable.
https://cetox.dev/html-encoder
UUID Generator
Every database eventually needs unique identifiers.
Instead of installing another library just to generate one UUID, having a browser-based generator is incredibly convenient.
It's simple. It works.
That's exactly what utility tools should do.
https://cetox.dev/uuid-generator
Fake Data Generator
Building applications with real customer data isn't a great idea.
Generating realistic fake names, emails, phone numbers, and addresses helps populate databases and test interfaces safely. It's one of those tools that becomes more valuable the more projects you build.
https://cetox.dev/fake-data-generator
JSON to Code
Typing interfaces by hand gets old very quickly.
Paste a JSON response...Generate matching code.
Whether you're using TypeScript or another language, this can save an incredible amount of repetitive work.
https://cetox.dev/json-to-code
Favicon Generator
Every website needs a favicon. Generating all required icon sizes manually is surprisingly annoying.
Upload one image...Download everything you need. Done.
https://cetox.dev/favicon-generator

Why I Built CETOX

CETOX isn't trying to replace your IDE. It isn't trying to replace your terminal.
It simply removes the tiny bits of friction that interrupt your workflow dozens of times every week.
Instead of searching Google for another utility website...you already know where everything is.
One bookmark. Twenty tools. No accounts. No installations.
Just fast browser-based utilities designed for developers.
I'm continuously adding:
More developer tools
Better UI and UX
More privacy-focused features
More AI-powered utilities
Better documentation
Educational blog posts

The goal isn't to become the biggest developer toolkit overnight. The goal is to build something developers genuinely enjoy using.

If you spend your day writing code, chances are you'll use at least a few of these utilities every single week. Instead of keeping dozens of bookmarks or repeatedly searching for the same tools, keep everything in one place.

If you'd like to try CETOX, you can explore all the tools here:
https://cetox.dev

If you have ideas for new tools—or features that would make your workflow better—I'd genuinely love to hear them.
Happy coding. :)

DEV Community: Cetox Dev

20 Free Browser-Based Developer Tools Every Programmer Should Bookmark.