Regex Match Tester
Test regular expressions against sample text, preview matches, inspect capture groups, toggle regex flags, and copy match results directly in your browser.
Enter a JavaScript-style regular expression pattern without the outer slash characters. Toggle flags below to control how matching works.
Regex Flags and Output Options
Paste logs, sample input, validation text, API responses, form data, or any text you want to test against the regular expression.
Highlighted Match Preview
Matching text is highlighted below so you can quickly check whether the pattern is selecting the intended content.
Match Output
Pattern: //gi Matches: 0
Testing Regular Expressions Against Real Text
Regular expressions are powerful, but they are easy to get wrong when you cannot see exactly what the pattern matches. A regex can pass over the wrong text, miss expected values, or capture groups in a different way than you intended.
This Regex Match Tester lets you enter a JavaScript-style regular expression, toggle common flags, test against sample text, inspect match indexes, review capture groups, preview replacements, and copy structured match results for debugging or documentation.
Debugging Regex Patterns Without Guesswork
- Enter a regex pattern without the surrounding slash characters.
- Choose flags such as global, ignore case, multiline, or dot all.
- Paste the text you want to test.
- Review highlighted matches, indexes, capture groups, and named groups.
- Copy the results or enable replacement preview when needed.
Common Regex Match Tester Use Cases
- Testing validation patterns for emails, URLs, IDs, and codes.
- Debugging capture groups before using regex in code.
- Extracting values from logs, API responses, or pasted text.
- Checking multiline matching behavior before using a pattern.
- Previewing replacements with JavaScript replacement syntax.
- Documenting regex examples with sample input and expected matches.
Example Regex Match
Pattern:
\b[A-Z0-9._%+-]+@[A-Z0-9.-]+\.[A-Z]{2,}\b
Flags:
gi
Text:
Contact support@example.com or billing@example.org.
Matches:
support@example.com
billing@example.orgUnderstanding Regex Flags
Regex flags change how the same pattern behaves. The global flag finds all matches. Ignore case allows uppercase and lowercase variants. Multiline changes how line anchors behave. Dot all allows the dot character to match line breaks. Unicode mode improves behavior with Unicode-aware patterns.
Testing flags together is important because a pattern that works on one line may behave differently across a long text block, log file, or copied API response.
Frequently Asked Questions
What is a regex match tester?
A regex match tester checks a regular expression against sample text and shows which parts of the text match the pattern.
Should I include slash characters around the pattern?
No. Enter only the pattern body. For example, use \d+ instead of /\d+/g, then select flags separately using the checkboxes.
Does this support capture groups?
Yes. The match details section shows numbered capture groups and named capture groups when your pattern includes them.
Can I preview replacements?
Yes. Enable replacement preview and enter replacement text. The tool uses JavaScript replacement behavior, including references such as $1 when applicable.
Why do I only see one match?
Enable the global flag to find every match. Without global matching, JavaScript regular expressions usually stop after the first match.
Is my regex or test text uploaded anywhere?
No. Regex testing happens directly in your browser, and your pattern and test text are not uploaded to a server.