Developer Tools
Regex Tester
Test a regex pattern against pasted text and read match counts, match locations, and capture values without sending data to a server.
Output will appear here.
What this tool does
Regex Tester validates a JavaScript-style regex against your sample text and shows the pattern used, active flags, match count, and matched values for quick debugging.
Common use cases
Validate and debug regular expressions quickly by testing patterns against sample text and reviewing captured matches.
Use Regex Tester when you are working with copied API payloads, logs, encoded values, config snippets, identifiers, or debugging data and need a quick browser-local check before pasting the result into docs, tickets, tests, or another developer tool.
How to use it
- Enter a regex pattern in the first line (for example: /pattern/gi).
- Paste the text to test on the following lines.
- Review match count and line-by-line match details.
- Copy the diagnostics and use them in your Regex Escape or Regex Match Extractor flow when needed.
Example workflow
Copy a small payload or encoded value from an API response, request URL, log line, or config file. Run the focused check here, confirm the output is readable, then continue with related developer data tools such as validation, formatting, decoding, timestamp conversion, or CSV/JSON conversion.
Privacy note
Client-side only: regex testing and all match diagnostics are computed in your browser. Your pasted text is not uploaded or stored.
FAQ
Can I test regex flags in this tool?
Yes. Paste either /pattern/flags syntax or a plain pattern to default to case-sensitive global matching in-browser.
Can I see capture groups?
Yes. Capture groups are shown for matches that include parenthesized groups.
Does this upload my text?
No. Regex testing runs locally in your browser, and your text is not uploaded or stored.
Explore more tools
Browse the Developer Tools hub or continue with the Developer Data Toolkit when this task is part of a larger workflow.