Testing whether a regex matches something is only half the actual problem when the pattern is destined for a find-and-replace operation, since a replacement string with capture group backreferences, $1, $2, and so on, can silently produce something completely different from what was intended if a group is numbered wrong or a backreference points at the wrong part of the match. This tool tests a regex pattern against sample text and previews exactly what a replacement string produces, backreferences included, before that pattern gets used in an actual find-and-replace on real files or code. Useful for confirming a replacement string's backreferences pull the right captured groups into the output, catching a pattern that matches correctly but replaces incorrectly, or previewing a bulk find-and-replace safely before running it for real.
Test regex patterns with live match highlighting, capture groups, and replacements. The Regex Match Tester is one of 900+ free developer tools on Toolblip - all open to use without a signup.
How do I use the Regex Match Tester?
Open the Regex Match Tester on this page, paste or upload your input, and the result updates as you type. Use the copy button to grab the output, or adjust options to tune the result. Nothing you enter leaves your browser.
Is the Regex Match Tester free to use?
Yes. The Regex Match Tester is a free online tool on Toolblip - no signup, no account, no hidden usage limits. It runs in your browser and works on desktop and mobile.
Is the Regex Match Tester safe and private?
Yes. The Regex Match Tester processes your data entirely client-side, so nothing you paste is uploaded or stored on any server. It's safe to use with internal snippets, private keys for debugging, or any other sensitive content you'd rather not send to a remote service.
What kind of output does the Regex Match Tester produce?
The Regex Match Tester produces clean, formatted output that you can copy or download with a single click. The output is tailored to the tool's purpose — formatted code, converted data, transformed text, or processed media — and is ready for immediate use in your project or workflow.
Does the Regex Match Tester work on mobile devices?
Yes. The Regex Match Tester is designed to work on any device with a modern browser, including phones and tablets. The interface adapts to smaller screens, and the core functionality — paste input, transform, copy output — works the same way regardless of your device.
Do I need to install anything to use the Regex Match Tester?
No. The Regex Match Tester runs entirely in your browser - no downloads, no accounts, no API keys. Paste your input, get the output, copy it back into your editor.
Can the Regex Match Tester handle large input files or long text?
Yes. The Regex Match Tester processes everything locally in your browser, so the only limit is your device's available memory. There are no arbitrary caps on input size, character count, or processing time that you would typically encounter with server-based tools.
Can I use the Regex Match Tester offline?
Once the page has loaded, the Regex Match Tester continues to work without an internet connection. Bookmark this page and return to it anytime - all logic runs locally.