Regex Generator
Fast, accurate and free online regex generator tool running directly in your browser.
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1Enter data
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2Click the button
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3Get the result
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return "Result ready in 0.1s";
}
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{
"regex": "/[A-Z0-9._%+-]+@[A-Z0-9.-]+\\.[A-Z]{2,}/i",
"mode": "email",
"flags": "i",
"find_all": "1",
"match_count": 2,
"matches": [
"[email protected]",
"[email protected]"
],
"notes": [
"Email template aims for practical matching (not full RFC compliance)."
],
"error": null
}
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Other tools you may find usefulRegular expression generator - quickly creating text matching patterns
Regular expressions (regex) are powerful mathematical rules for searching, validating and manipulating texts in the application's source code. With one line of regex, the programmer can verify that the user has entered the correct e-mail address, a strong password (containing numbers, letters and special characters), the correct date or bank account number. However, for many people, including novice developers and testers, learning and writing regular expressions correctly is a huge barrier due to the complex syntax. Our free online regular expression generator (regex generator) solves this problem. It allows you to select typical validation patterns from a ready-made list, specify logical rules and flags, and then automatically generates the correct regular expression code, which you can copy with one click.
This will save you time spent searching through documentation and avoid common syntax errors in your scripts.
Ready-made regex patterns and their importance in data validation
Our generator contains a set of the most popular and useful patterns that are used every day in web forms and databases. The table below shows the structure of these expressions:
| Validation target | Generated regular expression (standard) | Description of how the pattern works | Examples of valid data |
|---|---|---|---|
| E-mail address | ^[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}$ |
Checks for alphanumeric characters, monkey symbol (@), domain name and min. 2-letter TLD ending. | [email protected], [email protected] |
| Polish postal code | ^\d{2}-\d{3}$ |
Verifies the format of exactly two digits, a dash and three digits. | 00-950, 60-123 |
| Phone number (PL) | ^(?:\+48)?\s?\d{3}\s?\d{3}\s?\d{3}$ |
Matches 9-digit phone numbers, optional preceded by the Polish dialing code +48 and spaces. | +48 500 600 700, 123456789 |
| IP address (IPv4) | ^(?:(?:25[0-5]|2[0-4]\d|[01]?\d\d?)\.){3}(?:25[0-5]|2[0-4]\d|[01]?\d\d?)$ |
Validates four dot-separated octets, where each value must be between 0 and 255. | 192.168.1.1, 8.8.8.8 |
| Date in ISO format (YYYY-MM-DD) | ^\d{4}-(?:0[1-9]|1[0-2])-(?:0[1-9]|[12]\d|3[01])$ |
Checks the 4-digit year, hyphen, month (01-12) and day (01-31). Does not verify leap years. | 2026-06-18, 1990-12-31 |
How do the regular expression generator and PCRE engine flags work?
The generator analyzes the options you selected in the interactive form and composes them into logical strings of characters (tokens) consistent with the regex engine specifications. Additionally, it allows you to configure modifiers, i.e. the so-called expression flag:
- Ignore case (
iflag):The generated expression will not be case sensitive in matches. - Global match (
gflag):Finds all matches in text, instead of stopping at the first match (useful in JavaScript). - Multiline mode (
mflag):Makes the start (^) and end ($) anchors match the start and end of every single line of text, not just the entire document. - Unicode character support (
uflag):Guarantees stable operation with Polish diacritics and special symbols.
How to generate a regex pattern step by step?
We have designed our gene