Text & Regex
Regular Expression Live Tester, Matcher & Pattern Explainer
Test regular expressions in real-time with global flags (g, i, m, s), capture group inspection, and instant match highlighting.
Input Source Content
Output Result
About Regex Live Tester & Explainer & Security Considerations
Everything you need to know about how this utility processes data safely in your browser.
What do regex flags (g, i, m, s, u) do?
`g` matches all occurrences globally, `i` makes matching case-insensitive, `m` enables multi-line mode, and `s` allows dot to match newlines.
How can I prevent Catastrophic Backtracking (ReDoS)?
Avoid nested quantifiers like `(a+)+` and use atomic groups or possessive quantifiers to prevent exponential execution time.