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Build and test JavaScript regular expressions with Email, URL, Phone, and Username presets, custom pattern editing, flags gimsyu (default i), live Matched / No match feedback, and Copy regex as /pattern/flags — all in your browser.
Also try the JSON Formatter, Cron Expression Generator, and more in Utility tools.
Last updated: May 19, 2026 · Published: 2026-04-09 · Updated: 2026-05-19
Regex output
/^[A-Za-z0-9._%+-]+@[A-Za-z0-9.-]+\.[A-Za-z]{2,}$/i
Match result: Matched
Tip: start with a preset and then edit gradually. Small regex changes can create big behavior differences.
A regex generator helps you assemble regular expressions for validating and searching text — emails, URLs, phone numbers, usernames, or fully custom rules. Muxgen loads proven preset patterns, lets you edit syntax and flags, runs RegExp.test on sample input, and copies a slash-wrapped literal for your code.
Testing runs client-side — no upload to Muxgen servers and no account required.
Three steps to tested regular expressions.
Click Email, URL, Phone, Username, or Custom — default is Email with hello@example.com test text.
Refine the Pattern textarea (3 rows, monospace); set Flags gimsyu — default i.
Check Match result in the output panel, then Copy regex for /pattern/flags into your codebase.
Every control in the live regex generator component.
Email | URL | Phone | Username | Custom — loads PRESET_PATTERNS except Custom uses customPattern state.
Editable monospace pattern — changing text forces Custom preset; displays active pattern from preset or custom.
Text input — non-gimsyu characters removed on change; passed to new RegExp(pattern, flags).
4 rows — sample string for .test(); updates match result live without a separate Run button.
Emerald box showing full literal /pattern/flags identical to clipboard copy format.
Valid regex: Matched (emerald) or No match (amber). Invalid syntax: Regex error in red with parser message.
Full-width button — copies fullRegex string; Copied! for two seconds.
Any pattern edit sets preset to custom so presets do not overwrite your manual changes.
Exact patterns loaded from PRESET_PATTERNS in the component.
^[A-Za-z0-9._%+-]+@[A-Za-z0-9.-]+\.[A-Za-z]{2,}$ — local part, domain, TLD letters 2+.
Optional http/https, domain segments with dots, optional path — ^(https?:\/\/)?([\w-]+\.)+[\w-]{2,}(\/\S*)?$
^\+?[0-9\s().-]{7,20}$ — optional plus, digits and common separators, length 7–20.
^[a-zA-Z0-9_]{3,20}$ — alphanumeric and underscore, length 3 to 20.
Uses customPattern state — starts as email pattern until you pick another preset or edit.
Engine is browser RegExp — flags and syntax follow ECMAScript rules in modern browsers.
After regex extracts JSON from logs, paste into the JSON Formatter for readable output. Schedule jobs matched by cron patterns with the Cron Expression Generator.
Test GUID Generator output against custom ID regex before shipping API validators.
Aligned with the live regex generator component.
Email, URL, phone, and username patterns as one-click starting points.
testText, pattern, and flags changes re-run RegExp.test immediately.
Edit any preset into a bespoke expression without leaving the tool.
Only valid JavaScript flag letters survive — reduces typo syntax errors.
Exports /pattern/flags ready for code snippets and documentation.
No sign-up; patterns and test strings stay in the browser.
Where regex generation helps developers move faster.
Prototype email, URL, phone, and username rules before adding to React or Zod schemas.
Test query params and body fields against regex before server-side enforcement.
Iterate patterns against sample log lines until Matched confirms capture intent.
Find rows matching phone or URL presets before bulk normalization jobs.
Tune username or email patterns for admin dashboards and support tools.
Compare preset structure, flip flags, and read error messages when syntax breaks.
Presets, flags, testing, and related Muxgen utilities.
Presets load known patterns; any textarea edit moves to Custom for full control.
Regex matches text; JSON Formatter requires valid JSON tree structure.
This UI shows boolean match — use g flag in your app when you need all occurrences.
Case-insensitive email test on load — remove i or add explicit case classes for stricter rules.
Slug generator transforms strings; URL preset only validates shape.
Shareable URL and presets — no VS Code extension install required.
Terms used in the generator UI.
Pattern language for matching character sequences — implemented here as JavaScript RegExp.
Built-in regex string in PRESET_PATTERNS for email, url, phone, or username.
Modifiers g global, i ignoreCase, m multiline, s dotAll, u unicode, y sticky.
Displayed and copied string formatted as /pattern/flags with slashes around both parts.
Method used to return true or false for the current test text against compiled regex.
Mode where pattern comes from customPattern state after manual edits.
Keep patterns maintainable and production-ready.
Pick Email, URL, Phone, or Username before hand-writing every token.
Paste invalid strings and confirm No match before trusting a pattern in production.
Comment why a custom branch differs from the preset — future you will thank the team.
Keep quantifiers bounded; test long inputs if you extend presets with nested groups.
Client regex should mirror backend rules — this tool prototypes both sides.
Some languages need different regex literals — adjust slashes when pasting from Copy regex.
Habits that pair with presets, live test, and Copy regex.
hello@example.com with i flag should show Matched on first load — confirms tool works.
Click URL or Phone to load different PRESET_PATTERNS without typing from scratch.
Invalid group or unclosed bracket shows native RegExp parser message in the result panel.
Typing x in flags field is removed — only gimsyu persist.
Extract JSON from logs with regex, then paste into JSON Formatter for pretty-print.
Paste GUID Generator output into test text with a custom UUID pattern.
Presets, exact patterns, flags gimsyu, RegExp.test, copy format, custom mode, and privacy.
Explore more tools in the directory.
Validate and pretty-print JSON payloads you filter with regex in logs or APIs.
Build five-field cron strings for schedulers — another structured syntax tool.
Mock API keys whose formats you can validate with custom regex patterns.
UUID v4 output to test ID-matching regex against real identifier shapes.
Strong passwords — pair with username preset for signup form validation rules.
SEO slugs — compare slug output against URL preset patterns in tests.