How to use this tool
- Enter a regular expression pattern without surrounding slash characters.
- Choose JavaScript regex flags such as g, i, m, u, or y.
- Paste test text and click Test regex to see highlighted matches and captured groups.
What you can use Regex Tester for
Test regular expressions against sample text with flags, highlighted matches, match counts, and captured groups.
- Debug email, URL, SKU, log, or validation patterns
- Check whether a regex is too broad or too narrow
- Document sample matches for teammates
- Learn how flags and captured groups change results
Example workflows
| Email-like text | Use a simple pattern to find email-looking strings in test copy. |
|---|---|
| Log parsing | Capture date, status, or ID groups from sample log lines. |
| Validation draft | Try a pattern before placing it into form validation code. |
Privacy, accuracy, and limits
This tool is designed for fast everyday work in a browser. Review outputs before using them in production systems, financial decisions, health decisions, legal documents, or other high-stakes workflows.
- The tester uses the JavaScript RegExp engine in your browser.
- Regex behavior differs between programming languages, so verify production patterns in the target environment.
- Avoid testing private logs or customer records on shared devices.
Best practices
Use safe sample data, verify important results in the destination app, keep original files or text when editing matters, and choose the focused DailyWebTools utility that matches the task instead of forcing one tool to do every job.
Quality checklist
| Input | Use clean sample input and remove secrets, private files, or customer records before testing. |
|---|---|
| Result | Compare the output with a known example or the destination app when the task matters. |
| Limits | Remember that browser utilities are quick helpers, not replacements for official systems or expert review. |
| Next step | Open a related DailyWebTools utility if the workflow continues into formatting, conversion, calculation, or cleanup. |
For SEO and usability, this page focuses on one clear intent: helping visitors finish a specific task quickly while understanding privacy, accuracy, and verification limits. That makes the tool easier to trust and easier to compare with related utilities.
FAQ
Does this support JavaScript regex flags?
Yes. Use flags such as g, i, m, u, and y.
Does it upload my regex or text?
No. Matching runs in the browser.
Why do results differ from another language?
Different languages implement regular expressions differently, especially advanced features.
Can I test captured groups?
Yes. Captured groups appear in the matches output when the pattern contains parentheses.
Recommended guides
Use these related guides when the task needs examples, comparisons, platform checks, or a safer step-by-step workflow.
How to test regex patterns before using them
Learn how to test regex patterns safely with sample text, flags, captured groups, edge cases, and browser-based regex tools.
Read guide →Read guideHow to test regex for emails, URLs and IDs
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Read guide →Read guideJavaScript regex vs Python regex differences
Compare JavaScript and Python regex behavior around flags, groups, lookarounds, Unicode, and environment-specific testing.
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