Regex Tester
Test and debug regular expressions online, free. See live matches and capture groups against your text, entirely in your browser.
How to use Regex Tester
- Enter your regular expression pattern and flags (e.g. g, i, m).
- Type or paste the text to test against.
- See live matches and capture groups update as you type.
About Regex Tester
Regex Tester is a free Becoderr tool. It needs no sign-up, runs fast and privately, and works right in your browser for most tasks. For the few server-based tools, your files are processed in memory and discarded immediately after the operation.
Frequently asked questions
Which regex flavour is used?
JavaScript (ECMAScript) regular expressions, the same engine your browser uses.
What do the flags mean?
g = global (all matches), i = case-insensitive, m = multiline. The global flag is added automatically so all matches are listed.
Is this tool free to use?
Yes. Every tool on Becoderr is completely free with no sign-up required. Signed-in users get higher file-size limits.
Are my files safe?
Yes. Browser-based tools process files entirely on your device; nothing is uploaded. Server-based tools process files in memory and discard them immediately after the operation.
Is there a file size limit?
Server-based tools accept up to 5 MB for anonymous users and 50 MB when signed in. Browser-based tools are limited only by your device.