Regex Tester
Related tools
Validators and utilities that complement Regex Tester — same session, no sign-up.
Flags:
Click "Test" to run the regex against the test string.
Test regular expressions against text. See matches, capture groups, and flags (g, i, m, s).
About this tool
Enter a regex pattern and test string. Use g for all matches, i for case-insensitive, m for multiline, s for dotall. Invalid patterns show an error; valid ones list match index, full match, and capture groups.
For flavor comparison and step-by-step debug: regex101.com.
How to use this tool
- Paste your sample in the input (or fetch from URL if this tool supports it).
- Run the main action on the page to execute Regex Tester.
- Read the result, fix the source data or config, and re-run if needed.
What this check helps you catch
- Test regular expressions against text. See matches, capture groups, and flags (g, i, m, s).
- Limits called out in the description (what this tool does not verify — e.g. live network reachability, issuer databases, or strict schema contracts unless stated).
- Structural or syntax mistakes that would break parsers, serializers, or the next step in your workflow.
FAQ
- What does Regex Tester do?
- Test regular expressions against text. See matches, capture groups, and flags (g, i, m, s). Use the form above, then see “How to use” and “What this check helps you catch” for behavior detail.
- Is this a substitute for server-side validation?
- No. Use it for manual checks and triage; production systems should still validate and authorize on the server.
- Where does processing happen?
- Most validators here run in your browser. If a tool calls an API, that is stated on the page. See the site privacy policy for data handling.