About this tool
The Regex Tester lets you write and validate regular expression patterns against sample text, highlighting matches in real time and showing detailed results. It is built for developers, data analysts, and anyone who works with pattern matching in code, log files, or text processing tasks. No need to spin up a local environment or write throwaway scripts just to check if your pattern works.
Reach for this tool when you are writing a new regex from scratch and want instant feedback, or when you inherited a pattern from someone else and need to understand what it actually matches. It is also useful for debugging expressions that work in your head but not in production.
How to use it
- Paste or type your regular expression into the pattern input field.
- Enter or paste the sample text you want to test against in the text area.
- Select any flags you need, such as global, case-insensitive, or multiline.
- View highlighted matches in the text and review the detailed match list below.
- Adjust your pattern and watch results update immediately as you type.
- Copy a confirmed pattern directly from the tool for use in your code.
Pro tips
- Use named capture groups like (?
\d{4}) to make match results easier to read and reference in your code. - Test edge cases separately by pasting only the tricky input, not your full dataset, so you can isolate failures faster.
FAQ
Does it support all regex flavours?
The tool uses JavaScript regex syntax under the hood, so patterns follow ECMAScript rules. Flavour-specific syntax from Python or PCRE may not behave identically.
Is my test text stored anywhere?
Nothing you enter is sent to a server or saved. All matching runs locally in your browser.
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