UTILSBOX⚡ALL TOOLS54+
JSON.FORMATHub of five tools: format, validate, minify, convert to XML, and compare two JSON documents.//REGEX.TESTERReal-time regular expressions tester, cheatsheet, debugger and replacer.//PDF.SUITEMerge, split, extract text, rotate and convert PDF pages to images.//IMAGE.STUDIOIn-browser photo editor: crop, resize, filters, WebP/PNG and Base64 encoder.//HTML.BEAUTIFYHTML code beautifier, production minifier and entity encoder.//CSS.MINIFYCSS code formatter, production stylesheet minifier and CSS to SCSS converter.//SQL.FORMATTERSQL query beautifier, dialect translator (Postgres/MySQL) and minifier.//SVG.EXCALIDRAWInteractive vector visual editor powered by Excalidraw and SVG formatter.//TEXT.DIFFWord counter, reading time estimator and dual-text diff comparator.//YAML.CONVERTYAML & JSON bi-directional validator and formatter with syntax checking.//XML.PARSERXML document formatter, tree inspector and XML to JSON converter.//GRAPHQL.STUDIOGraphQL query & SDL formatter, minifier, AST field sorter and validator.//BASE64.CODECBase64 and URL-Safe encoder / decoder with full UTF-8 verification.//PASSWORD.GENCryptographically secure random password and entropy strength generator.//URL.STUDIO8-tool URL suite: encode, decode, validator, component parser and builder.//QR.STUDIOCustom QR code generator with embedded logos, colors, gradients and shapes.//ASCII.EXPLORERInteractive ASCII 0-255 table, Alt keyboard codes and CP437 symbols.//KEYCODES.LIVELive KeyboardEvent detector and JavaScript keycodes cheat sheet.//JWT.DEBUGGERJWT token decoder, claims inspector and Web Crypto signature verification.//BINARY.CODECBidirectional text to binary converter with digital rain and ASCII table.//CHARTS.STUDIOInteractive chart generator (bars, lines, pie, scatter) from CSV data.//UUID.V7Bulk generator for UUID v4, time-ordered v7, v1 and live UUID validator.//CSV.JSONBi-directional CSV to JSON converter with custom delimiters & table grid.//COLORS.STUDIOHEX/RGB/HSL/CMYK converter, palette harmonies and WCAG 2.1 contrast tester.//SEO.METASEO Meta Tags, Open Graph cards and real-time Google SERP card preview.//SCHEMA.JSONLDSchema.org JSON-LD structured data generator for Google Rich Snippets.//SITEMAP.XMLStandard XML Sitemap generator (Protocol 0.9) for Google Search Console.//ROBOTS.TXTRobots.txt generator, AI scraper blocking presets and live URL rule tester.//FAKE.DATASynthetic mock data generator: export records to JSON, CSV, SQL and TypeScript.//CLOCK.WORLDReal-time world clock with 3D holographic globe and 174 country timezones.//DATE.CALCDays between dates, exact age, business days, Unix timestamp and cron parser.//CALC.SUITESuite of 56+ online calculators: percentage, mortgage, loan, VAT, BMI & salary.//JSON.FORMATHub of five tools: format, validate, minify, convert to XML, and compare two JSON documents.//REGEX.TESTERReal-time regular expressions tester, cheatsheet, debugger and replacer.//PDF.SUITEMerge, split, extract text, rotate and convert PDF pages to images.//IMAGE.STUDIOIn-browser photo editor: crop, resize, filters, WebP/PNG and Base64 encoder.//HTML.BEAUTIFYHTML code beautifier, production minifier and entity encoder.//CSS.MINIFYCSS code formatter, production stylesheet minifier and CSS to SCSS converter.//SQL.FORMATTERSQL query beautifier, dialect translator (Postgres/MySQL) and minifier.//SVG.EXCALIDRAWInteractive vector visual editor powered by Excalidraw and SVG formatter.//TEXT.DIFFWord counter, reading time estimator and dual-text diff comparator.//YAML.CONVERTYAML & JSON bi-directional validator and formatter with syntax checking.//XML.PARSERXML document formatter, tree inspector and XML to JSON converter.//GRAPHQL.STUDIOGraphQL query & SDL formatter, minifier, AST field sorter and validator.//BASE64.CODECBase64 and URL-Safe encoder / decoder with full UTF-8 verification.//PASSWORD.GENCryptographically secure random password and entropy strength generator.//URL.STUDIO8-tool URL suite: encode, decode, validator, component parser and builder.//QR.STUDIOCustom QR code generator with embedded logos, colors, gradients and shapes.//ASCII.EXPLORERInteractive ASCII 0-255 table, Alt keyboard codes and CP437 symbols.//KEYCODES.LIVELive KeyboardEvent detector and JavaScript keycodes cheat sheet.//JWT.DEBUGGERJWT token decoder, claims inspector and Web Crypto signature verification.//BINARY.CODECBidirectional text to binary converter with digital rain and ASCII table.//CHARTS.STUDIOInteractive chart generator (bars, lines, pie, scatter) from CSV data.//UUID.V7Bulk generator for UUID v4, time-ordered v7, v1 and live UUID validator.//CSV.JSONBi-directional CSV to JSON converter with custom delimiters & table grid.//COLORS.STUDIOHEX/RGB/HSL/CMYK converter, palette harmonies and WCAG 2.1 contrast tester.//SEO.METASEO Meta Tags, Open Graph cards and real-time Google SERP card preview.//SCHEMA.JSONLDSchema.org JSON-LD structured data generator for Google Rich Snippets.//SITEMAP.XMLStandard XML Sitemap generator (Protocol 0.9) for Google Search Console.//ROBOTS.TXTRobots.txt generator, AI scraper blocking presets and live URL rule tester.//FAKE.DATASynthetic mock data generator: export records to JSON, CSV, SQL and TypeScript.//CLOCK.WORLDReal-time world clock with 3D holographic globe and 174 country timezones.//DATE.CALCDays between dates, exact age, business days, Unix timestamp and cron parser.//CALC.SUITESuite of 56+ online calculators: percentage, mortgage, loan, VAT, BMI & salary.//
MODULE 13 · DEV

Regex Tester

Test, explain, and replace regular expressions

//g
Test string73 bytes
Live preview2 matches
Contacts: john@example.com1 and support@utilsbox.dev2
This is not an email.
Matchescaptured groups
#1john@example.com[10–26]
#2support@utilsbox.dev[31–51]

Pattern breakdown

best-effort
[\w.+-]uno de estos caracteres: \w.+-
+1 o más veces
@texto literal "@"
[\w-]uno de estos caracteres: \w-
+1 o más veces
\.carácter literal "." (escapado)
[a-zA-Z]uno de estos caracteres: a-zA-Z
{2,}se repite 2 a veces
// Technical guide & specifications

How to test a regular expression on this page

The pattern, the flags, and the sample text sit at the top. Matches and the replacement show beside them.

1. Steps

Type the pattern without the slashes of a JavaScript literal. Turn on the flags you need: g walks every match, i ignores case, m makes ^ and $ apply per line. Paste the sample and read the highlighted matches and capture groups. In replace mode, $1 and $2 insert those groups.

2. An example

Pattern ([a-z0-9._%+-]+)@([a-z0-9.-]+\.[a-z]{2,}), flag i, text "Write to Ana@Utilsbox.biz today". The full match is the address, group 1 is Ana, and group 2 is Utilsbox.biz. A replacement of [$1] leaves [Ana] where the address was.

3. When the pattern stalls

A quantifier inside another quantifier, such as (a+)+, can take a very long time on a long near-match. If the page stops responding, shorten the sample and remove the nested quantifier before you ship that pattern to a server.

// Architecture & best practices

❓ Questions about the regex tester

Why does my pattern work in the terminal but not here?

This page uses the browser JavaScript engine. Lookbehind, possessive quantifiers, and some classes from other engines (PCRE, .NET) do not behave the same. Test the pattern on the engine that will run it.

Do I type /pattern/flags in the field?

No. The field is the pattern only. Flags are the buttons, not a trailing /g.

Is the sample text sent to a server?

Yes. Test and replace send the pattern and the text to the Utilsbox API and return the matches. They are not stored as an account. Do not paste data that must not travel over the network.

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Count words and characters in the same text.

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