Free Developer Tools
Free developer tools: JSON, HTML, CSS, JS and SQL formatters, Base64, hashes, JWT decoding, regex testing, UUIDs, cron and QR codes in your browser.
20 free tools, no sign-up required
JSON Formatter
Regex Tester
Base64 Decode and Encode
Hash Generator
UUID Generator
URL Encoder / Decoder
QR Code Generator
Color Palette Generator
Phone Number Formatter
Unix Timestamp Converter
CSS Formatter
CSV to JSON Converter
JWT Decoder
Cron Expression Generator
HTML Formatter
Image to Base64 Converter
JavaScript Formatter
Favicon Generator
SQL Formatter
Optical File Transfer: Send Files with QR Codes
About these free developer tools
The developer tools are small utilities for people who handle code, data formats and images in their day-to-day work. Each one does a single job, so the choice usually depends on the format in front of you.
- Formatters for JSON, HTML, CSS, JavaScript and SQL indent code for reading or minify it. The JSON formatter also validates input.
- Encoding tools cover Base64, URL encoding, images as data URIs, MD5 and SHA hashes and JWT decoding.
- Converters switch between CSV and JSON and between Unix timestamps and dates, and put phone numbers from the Gulf states, India and Pakistan into international format.
- Generators produce version 4 UUIDs, cron expressions, QR codes, favicons and color palettes. The Regex Tester highlights matches and capture groups as you edit a pattern.
- Optical File Transfer moves a file between two devices as a stream of QR codes read by a camera.
All of these run in the browser, and files opened in the image and file tools are read locally without being uploaded.
These free developer tools are for the moments when opening an editor or installing a package is more effort than the job itself: reading a minified API response, checking what a JWT carries, or turning a timestamp from a log into a date. You paste something in and copy the result out, and the tools keep nothing. They run on your own machine, the same way the browser's built-in web developer tools do, so nothing you paste is sent to a server.
If you work with JSON often, the guides on common JSON errors and formatting vs validating JSON explain the messages the JSON formatter shows, and what Base64 is covers when encoding helps and when it only makes data bigger.
Which tool should I use?
| If you need to… | Use |
|---|---|
| Format, validate or minify JSON | JSON Formatter |
| Make a QR code for a link or a piece of text | QR Code Generator |
| Encode or decode Base64 text and files | Base64 Decode and Encode |
| Convert a Unix timestamp to a date and back | Unix Timestamp Converter |
| Encode or decode a URL or query string | URL Encoder / Decoder |
| Generate random version 4 UUIDs | UUID Generator |
| Test a regular expression against sample text | Regex Tester |
| Get the MD5 or SHA-256 hash of a string | Hash Generator |
| Read the header, payload and expiry of a JWT | JWT Decoder |
| Convert CSV to JSON or JSON to CSV | CSV to JSON Converter |
| Beautify or minify HTML | HTML Formatter |
| Beautify or minify CSS | CSS Formatter |
| Beautify or minify JavaScript | JavaScript Formatter |
| Format a SQL query so it is easy to read | SQL Formatter |
| Build a cron schedule and see its next run times | Cron Expression Generator |
| Create favicons in standard sizes from one image | Favicon Generator |
| Turn an image into a data URI, CSS background or img tag | Image to Base64 Converter |
| Generate shades and matching colors from one base color | Color Palette Generator |
| Format a list of phone numbers into international format | Phone Number Formatter |
| Send a file between two devices using a screen and a camera | Optical File Transfer: Send Files with QR Codes |
Guides
How to Format JSON Online in Your Browser Without Installing Anything
Format JSON online in your browser: pick 2 spaces, 4 spaces or tabs, validate, minify and copy pretty printed JSON. Nothing is uploaded. Free, no sign-up. Read guide →
What Is Base64 Encoding and When Should You Use It?
What is Base64? Learn how Base64 encoding turns bytes into text, why the output is about 33% larger, what it is used for, and how to encode and decode it. Read guide →
Cron Expression for Every 5 Minutes: Explained with Examples
The cron expression for every 5 minutes is */5 * * * *. See how the step operator works, why it follows the clock, and copy 8 common cron schedules. Read guide →
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