Regex Tester & Explainer

Write, test, and understand regular expressions in real time. Paste your test string and see every match highlighted instantly. The built-in Explainer breaks down each part of your pattern into plain English — so you can understand what the regex actually does. Includes a library of 10+ common patterns. Everything runs in your browser.

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Cómo usar Regex Tester & Explainer

Completa tu tarea perfectamente en solo tres sencillos pasos.

Enter Your Pattern

Type a regex in the pattern box or pick one from the pattern library.

Set Flags

Toggle global (g), case-insensitive (i), multiline (m), or dotAll (s) flags.

Read the Explainer

The Explainer panel breaks each part of your regex into plain English, color-coded by type.

Preguntas frecuentes

Todo lo que necesitas saber sobre el Regex Tester & Explainer.

What is a regex?

A Regular Expression (regex) is a sequence of characters that defines a search pattern. It's used to find, match, extract, or replace text based on rules rather than fixed strings.

What does the 'g' flag do?

The 'g' (global) flag finds ALL matches in the string. Without it, the engine stops after the first match.

What's the difference between greedy and lazy quantifiers?

Greedy quantifiers (*, +) match as MUCH as possible. Lazy quantifiers (*?, +?) match as LITTLE as possible. For example, '<.+>' on '<b>text</b>' matches the entire thing greedily, but '<.+?>' matches just '<b>'.