Free Developer Tools

Sharp tools for developers, private by design.

Format, validate, convert, encode and test — twenty everyday developer tools that run entirely in your browser. Your code and data never leave your machine.

No sign-up100% client-sideNo uploadsNo daily limits

Formatters

Paste messy code or data and get clean, consistently indented output you can actually read.

JSON Formatter

Pretty-print JSON with your choice of indentation and clear error positions.

XML Formatter

Indent XML documents so nested elements are easy to follow.

HTML Formatter

Clean up messy markup with tidy, consistent indentation.

SQL Formatter

Put each SQL clause on its own line with consistent keyword casing.

Validators

Check whether a document is well-formed and find out exactly where it breaks when it is not.

JSON Validator

Check JSON for syntax errors and pinpoint where they are.

XML Validator

Check XML well-formedness and get plain-language error messages.

HTML Validator

A quick structural check for missing elements, unclosed tags and duplicate ids.

Encoders & Decoders

Everyday encoding jobs — Base64, URL encoding and QR codes — handled locally on your machine.

Base64 Encoder & Decoder

Encode and decode Base64 with proper UTF-8 handling.

URL Encoder & Decoder

Percent-encode text for URLs, or decode it back, in component or full-URL mode.

QR Code Generator

Turn text or a link into a QR code and save it as a PNG.

Minifiers & Beautifiers

Shrink JavaScript and CSS for production, or expand minified code back into something readable.

JavaScript Minifier

Strip comments and whitespace from JavaScript, conservatively and safely.

JavaScript Beautifier

Expand cramped or minified JavaScript into readable, indented code.

CSS Minifier

Compress CSS by removing comments and wasted whitespace.

CSS Beautifier

Turn compressed CSS into readable rules, one declaration per line.

Converters

Move data between XML, JSON, CSV and YAML without uploading it to a stranger's server.

XML to JSON Converter

Convert XML documents to JSON, keeping attributes and repeated elements.

JSON to XML Converter

Convert JSON into well-formed XML with an explicit attribute convention.

CSV to JSON Converter

Convert CSV rows to JSON objects using the header row as keys.

Testers

Build and debug patterns interactively before you ship them in your code.

Regular Expression Tester

Test a regex against sample text with matches, positions and groups.

Why everything runs in your browser

Most online tool sites send whatever you paste to a server. That is fine for a grocery list and a bad idea for API keys, production payloads and customer data. Every tool here is plain JavaScript executing on your own device: paste the messiest production JSON you have, and it is processed locally and forgotten the moment you close the tab. It also means the tools work instantly, with no queue, no account and nothing to install.