Regex Tester

Test a regular expression against text and highlight every match.

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pattern

flags

test string

matches (0)

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JavaScript regular expressions. Processing stops after two seconds or 5,000 matches. Match positions count UTF-16 code units.

Try a worked example

Example

Enter the pattern (\d{4})-(\d{2})-(\d{2}) with the flag g and the text Due 2026-10-23, paid 2026-11-01. There are 2 matches; the first captures 2026, 10 and 23.

Keep in mind

Patterns run in your browser's JavaScript engine. PCRE, Python, .NET and grep differ in details such as lookbehind, named groups and Unicode classes, so test the pattern again in the language where it will run.

About this tool

Build and test JavaScript regular expressions against sample text with live match highlighting and a match count. Set flags like g, i and m. A fast way to get a pattern right before pasting it into code.

JavaScript regular expressions. Processing stops after two seconds or 5,000 matches. Match positions count UTF-16 code units.

Frequently asked questions

Which regex flavour is this?

JavaScript (ECMAScript) regular expressions, using the same engine your browser and Node.js use.

What do the flags mean?

g matches all occurrences, i is case-insensitive, m makes ^ and $ match line boundaries.