Regex Generator: Plain English In, Working Pattern Out
Describe the pattern you want to match in plain English and get a correct, working regex. Works with Python, JavaScript, PCRE, .NET, and more. No account required.
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AI Regex Generator for Python, JavaScript, and PCRE
Writing regular expressions by hand is error-prone and slow. A misplaced quantifier or forgotten escape turns a working pattern into one that silently matches the wrong strings. Our AI regex generator takes your plain-English description and produces the correct pattern - with an explanation of what each part does so you can understand, test, and modify it.
Whether you need a basic email validator, a complex URL extractor, or a named capture group pattern for log parsing, describe it and get the regex in seconds. Specify your language (Python, JavaScript, Go, Ruby) for syntax-accurate output. Pair it with our Code Explainer to understand any snippet that uses regex, or use our Error Explainer when your pattern throws an exception. For extracting data with shell commands, see our Bash Command Generator for grep and sed patterns.
What the Generator Handles
Common Regex Patterns Library
Battle-tested starting points for the patterns developers request most. Copy one as-is or paste it into the generator and ask for adjustments.
| Matches | Pattern | How it works |
|---|---|---|
| Email address | ^[\w.+-]+@[\w-]+\.[\w.-]+$ |
Word characters, dots, plus, or hyphens before the @, then a domain with at least one dot. |
| URL (http/https) | https?:\/\/[^\s\/$.?#][^\s]* |
Literal http, optional s, then :// followed by any run of non-whitespace characters. |
| IPv4 address | ^(?:(?:25[0-5]|2[0-4]\d|1?\d?\d)\.){3}(?:25[0-5]|2[0-4]\d|1?\d?\d)$ |
Four octets of 0-255 separated by dots; the alternation rejects values like 999. |
| US phone number | ^\(?\d{3}\)?[-.\s]?\d{3}[-.\s]?\d{4}$ |
Three digits with optional parentheses, then 3 and 4 digits separated by an optional dash, dot, or space. |
| ISO 8601 date | ^\d{4}-(0[1-9]|1[0-2])-(0[1-9]|[12]\d|3[01])$ |
YYYY-MM-DD where the month group caps at 12 and the day group at 31. |
| UUID v4 | ^[0-9a-f]{8}-[0-9a-f]{4}-4[0-9a-f]{3}-[89ab][0-9a-f]{3}-[0-9a-f]{12}$ |
Hex blocks of 8-4-4-4-12; the literal 4 and the [89ab] class enforce version 4 specifics. |
| URL slug | ^[a-z0-9]+(?:-[a-z0-9]+)*$ |
Lowercase alphanumeric chunks joined by single hyphens, with no leading or trailing hyphen. |
| Hex color | ^#(?:[0-9a-fA-F]{3}){1,2}$ |
A hash followed by exactly 3 or 6 hex digits, covering both #fff and #ffffff forms. |
These are pragmatic patterns, not formal RFC validators. The email RFC, for instance, permits far stranger addresses than any sane form should accept. Ask the generator for a stricter or looser version to fit your use case.
Why Developers Use an AI Regex Generator
Even experienced developers look up regex syntax. The character class rules, the difference between greedy and lazy quantifiers, the way lookaheads interact with capture groups - it's a lot to hold in memory. Describing what you want and getting the correct pattern immediately is just faster. The AI also generates test cases you can use to verify the pattern before deploying it.
Python uses named groups as (?P<name>...), JavaScript uses (?<name>...). Specify your language and get syntax that actually runs.
Every generated regex includes a breakdown of what each part does - so you can modify it later without having to re-derive it from scratch.
Paste any regex you found in a codebase or Stack Overflow and ask what it does. Get a plain-English breakdown of every group and quantifier.
The generator shows example strings that match and strings that don't - so you can verify the pattern before running it on real data.
No regex documentation tab-switching. Describe, generate, copy, and test in one place. Available 24/7 with no account or login required.
Not quite right? Ask for a tweak in plain English - "also allow a plus sign at the start" - and the pattern is updated in the same conversation.
Common Regex Use Cases
The most frequent requests our regex generator handles.
Email addresses, phone numbers, postal codes, credit card numbers, URLs, IP addresses - validate user input with patterns you can trust.
Extract timestamps, error codes, IP addresses, and user agents from server logs with named capture groups for each field.
Find-and-replace across a codebase, reformat date strings, normalize whitespace, strip HTML tags - regex patterns for sed, grep, or your IDE.
Pull product codes, order IDs, prices, or any structured data out of unstructured text using capture groups and lookaheads. Combine with our JSON to CSV converter for export.
Regex Flavor Differences: PCRE vs JavaScript vs Python
A pattern that runs in one engine can throw a syntax error, or quietly match different text, in another. These are the differences that bite most often.
PCRE and Python's re support fixed-width lookbehind (?<=...); Python's third-party regex module allows variable width. JavaScript only gained lookbehind in ES2018, and older Safari versions throw a SyntaxError on it, so check your browser targets before shipping one.
Python writes named groups as (?P<year>\d{4}) and references them with (?P=year). JavaScript and PCRE use (?<year>\d{4}). PCRE accepts both spellings; Python's re rejects the bare (?<...> form outright.
In Python 3, \d matches any Unicode digit, including Arabic-Indic numerals, unless you pass re.ASCII. In JavaScript, \d is always ASCII 0-9, even with the u flag. The same applies to \w and \b, which is a common source of cross-language validation drift.
When you ask the generator for a pattern, name the engine it will run in. The same plain-English request produces subtly different output for Python, JavaScript, and PCRE, and that difference is exactly what keeps the pattern from breaking in production.
Frequently Asked Questions
(?=...), (?!...)), lookbehinds ((?<=...)), non-capturing groups, and atomic groups where supported by the flavor.re.MULTILINE in Python, /m in JavaScript).