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Probador de Regex

Texto y Código · Herramienta online gratuita

Probar regex con resaltado de coincidencias en vivo.

Equipo CoderNewbie
//g
Flags:
2 matches found
76 caracteres
2 matches
Contact us at [email protected] or [email protected] — replies within 24h.

Match Details

#1pos: 14"[email protected]"groups: [hello, example.com]
#2pos: 35"[email protected]"groups: [support, ez4code.dev]

Resaltado en vivo

Ve las coincidencias resaltadas en tiempo real mientras escribes tu patrón y texto de prueba.

Grupos de captura

Inspecciona cada grupo de captura de cada coincidencia, con posición y valor dispuestos claramente.

Soporte de flags

Activa las flags g, i, m y s para afinar tu patrón.

Cómo usar Probador de Regex

  1. 1Enter or paste your text or code into the input area.
  2. 2Choose the desired operation (format, convert, analyze, etc.).
  3. 3Click the action button to process.
  4. 4Copy the result from the output area.

Características

  • 100% gratis — sin registro, sin suscripción, sin anuncios
  • Funciona íntegramente en tu navegador — los datos nunca salen de tu dispositivo
  • Rápida y ligera — resultados instantáneos
  • Multiplataforma — funciona en escritorio, tableta y móvil

¿Qué es Probador de Regex?

Regular expressions (regex) are a pattern-matching language defined by IEEE POSIX and ECMAScript specifications. They describe search patterns using metacharacters and literals. A Regex Tester lets you evaluate patterns against test strings in real time, highlighting matches and capturing groups.

¿Cómo funciona Probador de Regex?

The tester compiles your pattern into a state machine (NFA/DFA) and applies it to the input string. Flags modify behavior: g (global), i (case-insensitive), m (multiline), s (dotAll), u (unicode), y (sticky). Match results show position, captured groups, and named groups.

Casos de uso habituales

  • Form validation — emails, phone numbers, postal codes
  • Log parsing — extract fields from structured log lines
  • URL routing — match path patterns in web frameworks
  • Search and replace — batch text transformations

Regex vs String Methods

String methods (includes, indexOf, startsWith) are simpler and faster for exact matches. Regex is necessary for pattern-based matching (e.g., 'all emails in a document'). For simple checks, prefer string methods; for flexible patterns, use regex. Overly complex regex can cause ReDoS (Regular Expression Denial of Service).

Seguridad y privacidad

This tool runs entirely in your browser. Beware of ReDoS when using regex in production — certain patterns (e.g., nested quantifiers like (a+)+) can cause catastrophic backtracking. Use timeouts or safe regex libraries for user-supplied patterns.

Detalles técnicos

Specifications: ECMAScript 2024 (MDN Reference), IEEE POSIX. Metacharacters: . * + ? ^ $ { } [ ] \ | ( ). Character classes: \d \w \s \b. Quantifiers: * (0+), + (1+), ? (0-1), {n,m}. Lookahead: (?=...) (?!...). Lookbehind: (?<=...) (?<!...). Named groups: (?<name>...).

Preguntas frecuentes

What is the difference between greedy and lazy quantifiers?

Greedy quantifiers (*, +) match as much as possible; lazy quantifiers (*?, +?) match as little as possible. Use lazy when you want the shortest match.

How do I test for a whole word?

Use word boundaries: \bword\b matches 'word' but not 'sword' or 'words'.

What are lookahead and lookbehind?

Lookahead (?=...) asserts what follows without consuming it. Lookbehind (?<=...) asserts what precedes. They are zero-width assertions useful for conditional matching.

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