Developer Playground

Write code. See it run.

A free live editor for HTML, CSS and JavaScript, plus a regex tester. Your code runs in a sandbox and stays in your browser.

Code playground

Edit the tabs, and the preview updates on its own. New to coding? Start with the Coding Academy.

Examples:

Test regular expressions with live highlighting. The pattern runs in your browser.

PatternFlags (g is always on)Test text

Already on GM, so nothing is duplicated here.

Format, minify and validate JSON, sort keys, and find syntax errors by line and column.

Encode and decode Base64 (UTF-8 and URL-safe) and URL text, or turn a file into a Base64 data URL.

Change text to UPPER, lower, Title or Sentence case, camelCase or snake_case, and clean up spaces and lines.

Pick a colour and convert it between HEX, RGB, HSL, HSV and CMYK. Pick from an image, get palette ideas.

Create strong random passwords with your choice of length and characters, and check an existing password's strength.

Count words, characters, sentences and paragraphs, with reading time, speaking time and top keywords.