How do I test a regex online?
Type your pattern into the Pattern field and your sample text into the Test Text box. Matches are highlighted live as you type, and capture groups appear below the result.
Is this regex tester free?
Yes. It is free with no signup, and all processing happens locally in your browser.
What regex flags are supported?
Global (g) and case-insensitive (i) flags are available as checkboxes. You can also write flags directly inside the pattern.
Does it show capture groups?
Yes. When your pattern contains groups, each match lists its captured substrings, including named groups.
What happens with an invalid pattern?
The tool shows a clear error message describing the problem instead of crashing, so you can fix the syntax and retry.
Can I use it for email or phone validation?
Yes. Common patterns for emails, phone numbers, and zip codes work because the tester uses the standard browser RegExp engine.
Is my test text private?
Completely. Nothing is uploaded; the pattern and text stay in your browser tab.
Does it support multiline text?
Yes. Paste multiple lines into the Test Text box; matches highlight across the whole sample.
Can I copy the highlighted result?
Use the Reset and Copy controls to clear the fields or copy output as needed within your own workflow.
Which regex flavor does it use?
It uses JavaScript regular expressions, the same engine that runs in modern browsers and Node.js.
Enter your regex pattern and the text you want to test. Matches are highlighted in real-time as you type. Capture groups are displayed below the result panel.
Yes, completely free with no signup required. All processing happens locally in your browser.
Global (g) and case-insensitive (i) flags are supported via checkboxes. You can also add other flags directly in the pattern.
A regex tester is a tool that lets you write a regular expression pattern and immediately see which parts of your sample text it matches. Instead of guessing whether a pattern like (?<=\$)\d+ works, you paste the pattern and a few lines of real text and watch the matches light up. Our online regex tester runs entirely in your browser using the JavaScript RegExp engine, so there is nothing to install and no server ever sees your data.
Developers reach for a regex tester when validating user input such as email addresses, phone numbers, and zip codes before a form is submitted. Analysts use it to parse server logs and pull out request paths or status codes. Office users clean CSV exports by matching repeated patterns, and editors build find-and-replace rules for a code base. Because the engine matches what your browser uses, what you test here is what runs in production JavaScript. For related structured-data work you can pair it with the JSON formatter or the Base64 encoder.
Escape special characters (. * + ? ( ) [ ] { } ^ $ | \) when you mean them literally. Anchor patterns with ^ and $ when you need a full-string match. Prefer non-greedy quantifiers (*?, +?) to avoid over-matching a long line. Always test edge cases: empty strings, very long input, and Unicode characters. Keep patterns readable with named groups (?<name>...) so teammates can follow your logic later.
Dedicated reference sites add community explanations and flavor switching, while command-line tools such as grep and sed run inside pipelines. A lightweight browser tester wins when you just need a quick check without signing up or pasting sensitive data into a third-party site. When you need to encode the matched output, the URL encoder and color picker sit one click away in the same toolkit.
Everything runs locally. Your pattern and test text never leave the page, which matters when you are checking live customer emails or internal identifiers. There is no account, no tracking script on the widget, and no upload step.
[\w.]+@[\w.]+\.\w+https?://(?<host>[^/]+)\b\d{3}[-.]?\d{3}[-.]?\d{4}\bTry each pattern in the box above and watch the groups fill in as you type.
