Dev Toolkit
Nine everyday developer utilities in one page. Runs entirely in your browser.
JSON formatter
JWT decoder
Header
Payload
Signature
signature not verified (client-side decode only)
Paste a token to decode its header and payload.
Base64 encode / decode
Drop a file or click to choose
Outputs base64. Files never leave your device. Up to 20 MB.
File base64
URL encode / decode
Paste a full URL to break it into parts.
Hash (SHA family)
Drop a file or click to choose
SHA-1, SHA-256, SHA-384, SHA-512 computed locally. Up to 50 MB.
Enter text or drop a file to compute digests.
UUID v4 generator
NIL UUID (reference)
00000000-0000-0000-0000-000000000000
Unix time converter
Current unix time (seconds)
0
Line diff
Enter text in both boxes to compare line by line.
Regex tester
/
/
Enter a pattern and a test string to see matches.
Replaced output
Quick reference
| Character classes | . | any character except newline |
| \d \D | digit / not a digit | |
| \w \W | word char / not a word char | |
| \s \S | whitespace / not whitespace | |
| [abc] [^abc] | any of / none of a set | |
| Anchors | ^ $ | start / end of string or line |
| \b \B | word boundary / not a boundary | |
| Quantifiers | * + ? | 0 or more / 1 or more / optional |
| {n} {n,} {n,m} | exactly n / n or more / n to m | |
| *? +? | lazy (fewest possible) | |
| Groups | (...) | capturing group |
| (?:...) | non-capturing group | |
| (?<name>...) | named capturing group | |
| a|b | match a or b | |
| Lookarounds | (?=...) | positive lookahead |
| (?!...) | negative lookahead | |
| (?<=...) | positive lookbehind | |
| (?<!...) | negative lookbehind |