Test regular expressions with live match highlighting, capture groups, flags and instant replace. Runs entirely in your browser.
Everything you need to know about testing and debugging regular expressions online.
A regular expression (regex) is a sequence of characters that defines a search pattern. It is used to match, find, or replace text in strings and is supported in virtually every programming language.
All standard flags are supported: g (global), i (case insensitive), m (multiline), and s (dot all). Toggle them with the flag buttons in the toolbar.
ReDoS (Regular Expression Denial of Service) occurs when certain regex patterns cause catastrophic backtracking, freezing the browser or server. This tool detects dangerous patterns and warns you before they cause problems.
The explainer breaks down your pattern into plain English. For example, \d+ is explained as "one or more digit characters". Great for learning and debugging complex patterns.
The tool generates ready-to-use snippets for JavaScript, Python, PHP, and Go — showing exactly how to use your pattern in each language.
Use word boundaries: word matches the exact word without matching partial words. For example, hello matches "hello" but not "helloworld".
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Support GetPDFMintA regex tester (regular expression tester) is an online tool that lets you write, test, and debug regular expressions in real time. Whether you're validating email addresses, parsing log files, or extracting data from strings, a regex tester shows you exactly which parts of your text match your pattern — instantly, without writing any code.
Enter your regular expression in the pattern field, then paste your test string below. Matches are highlighted
in real time. You can toggle flags like g (global),
i (case-insensitive),
and m (multiline) to control how the expression behaves.
Capture groups are shown separately so you can see exactly what's matched.
Developers use regular expressions daily — validating form inputs like emails, phone numbers, and URLs; searching and replacing text in code editors; parsing log files and API responses; extracting structured data from unstructured text; and building tokenizers and parsers. This tool supports JavaScript regex syntax compatible with Python, PHP, and Go patterns.