Regex Tester with Explanation
Test regex patterns with real-time matching and explanations
How to Use Regex Tester with Explanation
- 1Type your regular expression pattern in the pattern field.
- 2Toggle flags (g, i, m, s) as needed using the flag buttons.
- 3Enter or paste your test string in the text area below.
- 4Matches are highlighted in real time. The pattern explanation section shows what each token means.
About Regex Tester with Explanation
Test regular expressions online with real-time matching, syntax highlighting and human-readable explanations of your regex pattern. See matches highlighted instantly as you type. Toggle regex flags (global, case-insensitive, multiline, dotall) with one click. The pattern explanation breaks down each token so you can understand complex expressions.
Frequently Asked Questions
Which regex flavor does this use?
This tool uses JavaScript's built-in RegExp engine, which supports ECMAScript regex syntax including lookahead, lookbehind (in modern browsers), named groups and Unicode escapes.
Why are my matches not showing?
Make sure the 'g' (global) flag is enabled if you want to find all matches. Without it, only the first match is returned. Also check that your pattern syntax is correct — the error message below the pattern field will show any syntax issues.
Can I use this for regex replace?
Currently this tool focuses on matching and pattern explanation. Replace functionality may be added in a future update.