Choose a target language and supply the pattern. The generator handles the code wrapper; review regex features against the target engine.
Runs locally in your browserType a regular expression, choose one of the seven target languages and press Generate code. The pane returns a short program that compiles the pattern with that language’s own regex API and tests it against a sample string.
The snippet is assembled in the page: generating the examples sent no network request in testing, so the pattern never leaves the browser and the tool keeps working after the connection drops.
JavaScript: new RegExp("…") plus pattern.test(text). PHP: preg_match('~…~', $text, $matches) with a var_dump of the result, and the ~ delimiter escaped inside the pattern so that a literal tilde keeps its meaning. Go: regexp.Compile with MatchString, and the compile error routed through panic. Java: Pattern.compile and matcher(text).find(). Ruby: Regexp.new('…') and match?. Python: re.compile, search and bool(). C#: a verbatim @"…" string with Regex.IsMatch(text, pattern).
Every example keeps the sample text in a variable called text ($text in PHP) holding an empty string, and the pattern is escaped for that language’s string literal — backslashes, the quoting character, and \r or \n where the language needs them — so patterns such as say "hi", a\~b or a~b reach the target engine unchanged. Each snippet was executed against matching and non-matching input for those cases and returned the expected result.
The samples test an empty string, so most of them print a negative result until you replace text with your own input. Nothing is validated: a pattern that cannot compile — a lone backslash, an unclosed group — is copied exactly as typed and fails in the target language, and flags written as part of the pattern (/abc/i) stay literal text instead of becoming that language’s own options.
PHP runs on PCRE with the ~ delimiter, and PCRE has no \uXXXX escape: for a character such as é use \x{00E9} with a /u pattern. Go compiles with regexp, which rejects lookaround and backreferences, so the generated program panics on patterns that JavaScript or Python accept.
The tool copies the pattern text; it does not translate it between engines. Measured with the same pattern in three engines: ^b matches inside "a\nb" in Ruby, where ^ and $ anchor to lines, and does not match in JavaScript, Python or PHP. \d matches the Arabic-Indic digit ٣ in Python, and in PHP only with the /u modifier, while Ruby and JavaScript keep \d to the ASCII digits 0–9. Test the pattern in the target language before shipping it.