Regex Tester
Test regular expression matches, groups, and replacements in the browser. Named groups are supported, and the sample text is not uploaded.
- Open the tool
- Add the content you want to process
- Check the result before you copy or download it
Check the match
See which parts of a real sample match instead of only checking that the pattern compiles.
Inspect groups
Confirm a group captures the order id or date, not the surrounding text.
Preview replacement
Review the replacement before the pattern reaches production code.
Forgetting flags
Global, case-insensitive, and multiline flags change the match count. Test the flags your code uses.
Using only one positive sample
A match is not enough. Add text that must not match and check the boundary.
FAQ
Are named groups supported?
Yes. Paste (?<name>...) and inspect the group result.
Can I preview a replacement?
Yes. Review the replacement before copying the pattern into code.
Is the sample uploaded?
No. Matching, groups, and replacement stay in the browser and do not use credits.
How does this fit the regex generator?
The generator drafts a pattern. This tester checks it against samples.
Why does code behave differently?
Check flags, newlines, and whether global matching is enabled. Engine differences still need a separate check.
- Draft a pattern
Generate a candidate, then come back here to test it.
- Read the regex guide
See how to prepare positive and negative samples.
- Code Explainer
Explain code snippets, execution flow and potential issues for learning and review.
- SQL Generator
Turn plain-language requirements into SQL with assumptions and safety notes.
- Regex Generator
Generate regular expressions from plain-language requirements with explanations and examples.
- Diff Checker
Compare two texts line by line to spot additions, removals and edits.