Regex Tester

How to Use the Regex Tester

1. Enter your regular expression pattern in the pattern field (without the surrounding slashes).
2. Select flags such as g (global), i (case-insensitive), or m (multiline).
3. Paste your sample text into the test area.
4. Matches are highlighted live, with a match count and any capture groups listed below.

What is regex?

A regular expression is a sequence of characters that defines a search pattern. Instead of searching for an exact string, regex lets you describe a shape of text — for example "one or more digits" or "an email-like pattern" — and match anything that fits that shape. Regex is built into most programming languages, text editors, and command-line tools.

Common regex symbols

`.` matches any character, `\d` matches a digit, `\w` matches a word character, `\s` matches whitespace, `*` means zero or more, `+` means one or more, `?` means zero or one, `^` anchors to the start, `$` anchors to the end, and parentheses `()` create a capture group you can extract separately from the full match.

Common mistakes

The most common regex mistakes are forgetting to escape special characters like `.` or `(` when you mean them literally, using greedy quantifiers (`*`, `+`) when you meant a non-greedy version (`*?`, `+?`), and forgetting the global flag when you expect multiple matches instead of just the first one.

Example

Pattern: \w+@\w+\.\w+
Text: Contact us at hello@example.com or admin@example.com

Matches: hello@example.com, admin@example.com

Tips

• Test edge cases, not just the "happy path" input — empty strings, extra whitespace, and unexpected characters.
• Use non-capturing groups `(?:...)` when you need grouping but not extraction.
• Break complex patterns into smaller pieces and test each part separately.

Frequently Asked Questions