Regular Expression Tester

Inspect bounded PCRE matches and capture groups on a UTF8 text sample.

A pattern needs representative examples before it is used on a real dataset.

Test a small UTF8 sample and inspect matches, groups and byte positions.

Inputs and controls

Expression

Enter the body without delimiters. UTF8 mode is always enabled.

Expression

Unicode, Unicode, ignore case, Unicode, multiline, Unicode, ignore case and multiline, Unicode, dot matches newline, Unicode, all three modifiers

Sample text

Choose modifiers. Enter pattern body.
Paste or enter text to inspect.
Select Process input. Read the returned values alongside the assumptions below before copying, exporting or acting on the result.

Bounded PCRE matching keeps the test focused and exposes captured values.

Up to 100 matches. Byte offsets are shown. Backtracking and recursion limits bound work; this is PCRE, not JavaScript regex.

Up to 100 matches. Byte offsets are shown. Backtracking and recursion limits bound work; this is PCRE, not JavaScript regex.

Will the pattern behave identically in JavaScript?

Not necessarily. This tester uses PHP PCRE, whose rules can differ from JavaScript regular expressions.

What should I check before using Regular Expression Tester?

Check Pattern body, Modifiers and Text to inspect. Use the exact units shown beside the controls and replace any example values with your own inputs.

Source page last modified: 2026-10-04T16:58:29+00:00. This profile describes the tool; use its page to run it.

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