🎯 Regex Tester & Matcher

Using Regex Tester & Matcher

Build and debug a JavaScript regular expression against real sample text, such as extracting phone numbers from a log or validating an order code, before putting it in code.

How to use it

1. Type the pattern without surrounding slashes, for example \d{3}-\d{4} rather than /\d{3}-\d{4}/.
2. Enter flags: g finds every match, i ignores case, m makes ^ and $ work per line.
3. Paste representative text into Test String and read each match with its index and any named groups.
4. Use Preview share link to get a URL containing the example, and read the included text before copying it.

Worked example

Input and settings

Pattern \b\d{3}-\d{4}\b, flags g, text "Call 555-0199 or 555-0142."

Expected result

2 matches: 555-0199 at index 5 and 555-0142 at index 17.

Limits and common mistakes

• This uses JavaScript's regex engine; lookbehind, Unicode classes and flags behave differently in PCRE, Python or Java.
• A pattern that runs longer than 1.5 seconds is stopped, which catches catastrophic backtracking such as (a+)+$.
• At most 1,000 matches are listed.
• A share link carries your test text after the # sign, so it is not sent to the server, but anyone who has the link can read it.

Found a mismatch? Report a problem with a non-sensitive example. Read our privacy information before sharing inputs or links.