Regex Tester

Why use this tool

Regex Tester is designed for developers who need to iterate on pattern matching quickly without bouncing between IDE plugins and temporary scripts. Regular expressions are powerful but easy to get wrong, especially when combining groups, quantifiers, and escaping rules. This tool lets you enter a pattern, select flags, and immediately see highlighted matches in your test string, which makes debugging intent much faster than scanning raw output indices alone.

The interface emphasizes practical feedback. If your pattern is invalid, you get a readable error message instead of a broken UI state. If it is valid, every match is highlighted and listed, helping you verify both simple and edge-case behavior. This is useful for parsing logs, validating inputs, extracting IDs, and preparing sanitization rules. Because flags are entered separately, you can quickly experiment with global, case-insensitive, multiline, and unicode behavior to see exactly how matching changes.

Everything runs in your browser and does not transmit test text externally, which is useful when your samples include internal identifiers or user-like data. The output format is copy-friendly for sharing regex results in code reviews and support threads. Whether you are writing one-off validation logic or refining production parsing rules, this tester gives a dependable scratchpad for regex iteration with visual confidence.

How to use

1. Enter the regex pattern without surrounding slashes.
2. Enter flags such as g, i, m, or u.
3. Paste your test string in the input area.
4. Click Test Regex or press Ctrl+Enter.
5. Review highlighted matches and match list output.

Use cases / examples

• Validate email/phone input patterns before shipping.
• Extract IDs from server logs.
• Test multiline parsing rules for config files.
• Teach regex behavior with visual match previews.

FAQ

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