This tool breaks down a regular expression into parts and explains constructs: character classes, quantifiers, groups and assertions, helping you understand and modify it.
How do I figure out what a regex copied from someone else's code does?
Paste the expression into the input field and click "Explain" — the tool breaks it into parts (character classes, quantifiers, groups), explains each in plain language, and shows examples of matching strings.
Does it show strings that do NOT match the pattern?
Yes, besides matching examples the generator can show strings that do not fit the pattern — this helps you see the exact boundaries of what the regex actually validates.