Free Online Developer Tools

The formatters turn minified or hand-edited code into something you can read. The JSON Formatter pretty-prints JSON and tells you when it is not valid; the XML, HTML and CSS formatters indent markup and stylesheets without rendering or running them. The JSON to CSV Converter flattens an array of objects into a spreadsheet-ready file, and the HTML to Markdown Converter turns markup into clean Markdown for docs and README files.

For debugging, the Regex Tester highlights JavaScript regular expression matches and capture groups, the Base64 and URL encoders convert values in both directions, and the Unix Timestamp Converter translates epoch seconds into readable dates. The URL Parser splits a link into its host, path and decoded query parameters, and the JWT Decoder shows a token’s header and payload without verifying it. When you need fresh values, the UUID Generator and Password Generator use your browser’s cryptographic random number generator.

Because processing happens on your device, you can paste API responses, config files or tokens without them leaving your browser. Still, treat production secrets with the same care you would anywhere else.