Useful Developer Tools for Programmers

Formatters, decoders and generators that save a context switch — and why "runs in your browser" matters when you paste tokens.

Every developer has a mental list of small websites they visit ten times a day. Here is ours — collected in one place.

Make data readable

• JSON Formatter pretty-prints, minifies and sorts keys, with a collapsible tree for big responses.
• JSON Validator points to the exact line and column of a syntax error and warns about duplicate keys, which many parsers silently accept.
• XML Formatter for SOAP responses and config files.
• HTML, CSS and JavaScript formatters, plus a Code Minifier that reports how much you saved.

Decode and encode

• JWT Decoder shows the header and payload and turns exp and iat into readable dates. Remember: decoding is not verifying — the tool says so clearly.
• Base64 Encoder / Base64 Decoder, including files and URL-safe Base64.
• URL Encoder and HTML Entity Encoder.

Generate things

• UUID Generator for v4 and time-ordered v7 IDs, in bulk.
• Hash Generator for MD5, SHA-1 and SHA-256/384/512 checksums of text or files.
• Password Generator with entropy shown in bits.

Test patterns

The Regex Tester highlights matches live, lists capture groups and previews replacements. It also guards against catastrophic backtracking, so a bad pattern won't freeze your tab.

Why "in your browser" matters

Developers paste sensitive things: API responses, tokens, customer data. All of the tools above process input locally in your browser and don't send it to our servers. Even so, treat production secrets with care — rotate any token you have pasted somewhere you don't control.

See every developer tool.