Regular expression library

Matches a URL starting with HTTP or HTTPS without whitespace.

Example https://example.com/path?q=1

Matches four decimal IPv4 octets from 0 to 255.

Example 192.168.1.10

Checks common 11-digit number prefixes; does not look up number ownership.

Example 13800138000

Matches three or six hexadecimal digits with an optional hash.

Example #1A2B3C

Matches one or more characters in the common CJK ideograph range.

Example 你好，世界

Matches a decimal integer without a fraction, with an optional minus sign.

Example -42

Matches a decimal number with an optional fractional part.

Example 3.14159

Matches percentages from 0 to 100 inclusive. Rejects 100.5%.

Example 87.5%

Checks YYYY-MM-DD shape and month/day ranges, not calendar validity.

Example 2026-09-03

Checks the shape of an ISO 8601 date and time with a timezone.

Example 2026-09-03T12:30:00+08:00

Matches hours and minutes in 24-hour time.

Example 09:30

Checks the hexadecimal format of a version 4 UUID.

Example 550e8400-e29b-41d4-a716-446655440000

Starts with an ASCII letter; 3–16 letters, digits or underscores.

Example xt_tools_01

Matches lowercase ASCII letters and digits separated by single hyphens.

Example hello-world-2

Extracts a final alphanumeric extension of 1–10 characters.

Example report.pdf

Checks a common major.minor.patch version shape with optional suffixes.

Example v2.4.1-beta.1

Matches consecutive whitespace, useful for replacing it with one space.

Example hello world

Matches simple opening-tag shapes; this is not an HTML parser.

Example <section class="card">

Matches single-line text with matching single or double quotes. Rejects mismatched quotes and line breaks.

Example "hello"