Regex Tester

Test regular expressions online with matching, capture groups, highlighted preview, replacement, and common pattern library.

Regex Configuration

Regular Expression

No need to wrap with slashes; enter the pattern directly

Flags

g Global

i Ignore case

m Multiline

s Single line

u Unicode

y Sticky

Test String

Replace Pattern (optional)

Supports $1, $2 and other capture group references

Common Patterns

Email Address[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}

URLhttps?://[^\s]+

IPv4 Address\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}

Phone Number1[3-9]\d{9}

ID Number\d{17}[\dXx]

Date\d{4}-\d{2}-\d{2}

Time\d{2}:\d{2}:\d{2}

Hex Color#[0-9a-fA-F]{6}

Number-?\d+(?:\.\d+)?

Chinese Characters[\u4e00-\u9fa5]+

Match Results

Please enter a regular expression

Usage Guide

Features

A regular expression testing tool for real-time regex matching. Enter a regex pattern and test string to automatically compute all matches, showing match positions, match contents, and capture groups with yellow-highlighted match segments. Also supports replacement mode preview and quick pattern insertion.

Steps

Enter a pattern in the "Regular Expression" field (no slashes needed).
Select flags as needed (g for global match is default).
Paste the text to match in the "Test String" field; match results and highlight preview will display below in real-time.
To use replacement, enter the replacement string in the "Replace Pattern" field (supports $1, $2 etc. capture group references).
Click any card in "Common Patterns" to quickly insert a preset pattern.

Flag Descriptions

g - g Global
i - i Ignore case
m - m Multiline
s - s Single line
u - u Unicode
y - y Sticky

Notes

If g is not selected and multiple matches exist, only the first is returned. Replacement automatically enables the g flag to replace all matches. Zero-width matches (e.g., lookahead) are displayed with position indicators. All matching is done locally in the browser; data is not uploaded to any server.