Regular expressions are powerful and famously hard to write from memory. Describe what you want to match in plain English and get a working regex back, along with a breakdown of what each part does and a few test strings that should and shouldn't match.
Your result will appear here.
Pick the one matching your runtime: JavaScript for browser/Node, Python for re, PCRE for PHP/grep-style tools, Go for Go's RE2. Syntax like lookbehind isn't supported everywhere, so the flavour matters.
Yes. Paste the expression instead of a description and ask what it does, and you'll get a plain-English breakdown.
Always test against real data. Regex edge cases are subtle, and a pattern that looks right can still over- or under-match.