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Best Free Developer Tools

The best free online developer tools generate CSS, format and convert data, compare files, and handle the small jobs that fill a workday, all in your browser. All Tools Verse has a large set of free developer tools that run client-side with no sign-up and nothing uploaded. This guide picks the best free tool for each task, from a CSS gradient to a diff, a base64 encode, or a curl command rewritten for your language.

Best developer tools at a glance

Pick the task, then open the tool. Each is free and needs no account.

TaskBest free toolGood for
CSS gradientCSS Gradient GeneratorBackgrounds and buttons
Flexbox or GridFlexbox, Grid GeneratorPage layout
Compare filesDiff CheckerSpotting changes
Base64Base64 Encoder and DecoderEncoding data
Format JSONJSON FormatterReading and validating
curl to codeCurl to Fetch, Curl to PythonPorting API calls
URL slugSlug GeneratorClean page URLs

CSS generators

CSS generators write the code so you can tweak visually. CSS Gradient Generator and Box Shadow handle backgrounds and depth, Flexbox and Grid Generator build layouts, and Border Radius, Transform, Filter, and Animation cover effects. For modern looks there are Glassmorphism, Neumorphism, Clip Path, and a Media Query Generator for responsive rules.

CSS and HTML utilities

To tidy code, CSS Beautifier formats it and CSS Minifier shrinks it for production, while CSS Unit Converter moves between px, rem, and other units. For HTML, HTML Tag Stripper removes the markup from text, Excel to HTML Table turns a spreadsheet into a table, and BBCode to HTML converts forum markup.

Format and convert data

For everyday data, JSON Formatter reads and validates JSON, and JSON to TypeScript with C# Class from JSON turn a sample into typed code. BSON to JSON handles the MongoDB format, and for encoding there are Base64, Base32, and Base58.

Convert curl commands

To turn a curl command from the docs into code, Curl to Fetch writes JavaScript, Curl to Python Requests writes Python, and Curl to PHP Curl writes PHP, so you can drop an API call straight into your project.

Compare and inspect

To find what changed, Diff Checker highlights the differences between two texts line by line. URL Parser breaks a link into its parts, and Slug Generator turns a title into a clean, lowercase URL slug.

Sysadmin and scheduling

For server work, Chmod Calculator builds Unix file permissions, Crontab Generator and Cron Parser Next Runs handle scheduled jobs, Docker Compose Generator scaffolds a config, and Epoch Converter turns Unix timestamps into dates.

How to choose the right tool

Match the tool to the job. Styling is a CSS generator, and cleaning code is the beautifier or minifier. Reading or typing data is the JSON and base tools, and porting an API call is a curl converter. Spotting changes is the diff checker, and server tasks are the chmod, cron, and Docker tools. Each is a single focused tool, so you stay in flow instead of switching apps.

Trusted alternatives

VS Code with extensions covers formatting, diffing, and more inside the editor, browser developer tools let you tweak CSS live, and CodePen is great for prototyping. For API work, Postman imports and runs curl commands. For a single quick generate, convert, or compare, a focused browser tool is faster.

Frequently asked questions

What is the best free CSS gradient generator?

Use CSS Gradient Generator to design a gradient visually and copy the CSS. Box Shadow, Flexbox, and Grid generators cover the other common layout and effect needs.

How do I compare two files or texts?

Paste both into Diff Checker, which highlights added, removed, and changed lines so you can see exactly what is different.

How do I encode or decode base64?

Use Base64 Encoder and Decoder to convert text or data both ways in your browser, with Base32 and Base58 available for those formats.

How do I convert a curl command to code?

Paste it into Curl to Fetch for JavaScript, Curl to Python Requests for Python, or Curl to PHP Curl for PHP, then drop the result into your project.

Are these developer tools free and private?

Yes. Every tool is free with no account, and the work happens in your browser, so code and data you paste are never uploaded.

How do I generate a cron schedule?

Use Crontab Generator to build the schedule from simple options, and Cron Parser Next Runs to confirm when an existing expression will fire next.

This guide is part of our roundup of the best free online tools.

ATV

Written by Nick (ATV Team)

We build and maintain the 600+ free, client-side tools on this site, and every guide is written against the tools themselves: each figure is computed and checked before it is published, and every linked tool is tested in the browser. More about how we work on the about page, and the full library of guides lives on the blog.