Free Developer Tools
Everyday utilities for developers: formatters and validators for JSON, XML, YAML, SQL, HTML, CSS and JavaScript, plus regex testing, JWT decoding, Base64 and URL encoding, cron, UUIDs, hashes and subnet maths. Your code and data stay on your device.
31 free tools · no sign-up
JSON Formatter
Format, validate and minify JSON.
Base64 Encode / Decode
Encode or decode Base64 strings.
Code Share
Paste code and share it with a short link.
URL Encode / Decode
Escape and unescape URL components.
Hash Generator
MD5, SHA-1, SHA-256 and SHA-512 for text or files.
Regex Tester & Explainer
Test a regular expression and see what it means.
Markdown Preview
Write Markdown and preview it live.
Color Picker
Pick colours and convert HEX, RGB, HSL.
Cron Generator & Explainer
Build or explain cron expressions and see the next runs.
UUID Generator
Generate v4 or v7 UUIDs in bulk, up to 10,000.
JSON Validator
Check JSON and see exactly where an error is.
XML Formatter & Validator
Pretty-print, minify and validate XML.
YAML Formatter & Validator
Validate YAML and convert between YAML and JSON.
SQL Formatter
Beautify SQL queries with clear indentation.
HTML Formatter
Beautify or minify HTML.
CSS Minifier
Minify or beautify CSS.
JavaScript Beautifier
Re-indent minified or messy JavaScript.
JavaScript Minifier
Strip comments and whitespace from JavaScript.
HTML Entity Encoder / Decoder
Escape and unescape HTML special characters.
JWT Decoder
Read a JSON Web Token and check its signature.
Unix Timestamp Converter
Convert Unix time to dates and back.
URL Parser
Split a URL into parts and edit its query string.
User-Agent Parser
See which browser, OS and device a user-agent is.
HTTP Status Codes
Every HTTP status code explained in plain English.
IP Subnet Calculator
Network, mask, host range and subnets for IPv4.
SQL Query Builder
Build SELECT, INSERT, UPDATE and DELETE queries.
Image to Base64
Turn an image into a data URL, or Base64 back into an image.
SVG Optimizer
Shrink and clean SVG files, and strip scripts.
Color Contrast Checker
Check text colours against WCAG AA and AAA.
CSS Gradient Generator
Linear, radial and conic gradients with CSS and PNG.
CSS Box Shadow Generator
Layered box shadows with a live preview and CSS.
Questions
Are these Developer tools really free?
Yes. All 31 tools in this category are free to use, with no sign-up and no watermark on your files.
Are my files and text kept private?
30 of these tools run entirely in your browser, so nothing is uploaded. The others send your file to our server only to process it and delete it as soon as the result is sent back. Each tool page says which kind it is.
Do I need to install anything?
No. The tools work in any modern browser on Windows, Mac, Linux, Android and iPhone.