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Regex Tester & Pattern Debugger

Test a regular expression against your own sample text with live match highlighting, capture groups and flags: plus a plain-language breakdown of what every part of the pattern actually does.

Everything happens locally in your browser. Nothing you paste is uploaded, logged or stored on our servers.

Product demo

Watch explai answer one real business question

A recording of the product itself. At the top, the question someone types in: roll a promotion that grew revenue 12% out across all European stores. Below it, explai's answer: it checks that claim against the real sales data, shows every reasoning step, and comes back with a chart and a clear recommendation against the rollout. Under 10 seconds, starts by itself, nothing to click.

That was one question, on our data. In measured deployments teams save about three hours per person a day, and a week of repeatable analysis comes back in roughly five minutes. A private sandbox is waiting for your data: upload a CSV and ask your first question in a few minutes.

FAQ

Questions people ask about this tool

How do I test a regular expression online?

Enter your pattern and a block of sample text. Matches are highlighted as you type, with capture groups listed per match, so you can see immediately whether the pattern is too greedy or too narrow.

What does this regex do?

The explainer walks the pattern token by token (character classes, quantifiers, groups, anchors, lookarounds) and describes each one in plain language, so you can read an inherited pattern instead of reverse-engineering it.

Which regex flavour does the tester use?

JavaScript (ECMAScript) regular expressions, the same engine your browser uses. Most patterns port cleanly to Python, Java or PCRE, but named groups, lookbehind and Unicode property escapes differ between flavours.

Beyond the toolbox

Small tools save minutes. Real analysis saves weeks.

explai is an AI data agent that runs the whole analysis: root causes, forecasts, and every answer cited back to your own numbers. The same instant-answer feeling as these tools, on your business data.

Regex Tester & Explainer: Free Online | explai