# Regex Generator

> Describe what you want to match in plain English. Get a regex pattern with a live test panel and a token-by-token breakdown.

- URL: https://generate.now/regex
- Category: text
- Price: free, no account required
- AI-powered: yes
- Last updated: 2026-08-27

## What it does

AI-powered natural language to regex. Generates a pattern with flags, explains each token, and lets you test against sample text with live highlighting. Built for the moments when you need a regex now and don't want to remember whether \d needs escaping.

## When to use it

- Match all email addresses in a paragraph
- Extract URLs from a log file
- Validate UK postcodes or US ZIP codes
- Find anything that looks like a phone number
- Pull out semantic version strings like v1.2.3

## Examples

### match all email addresses except gmail

```
\b[A-Za-z0-9._%+-]+@(?!gmail\.com)[A-Za-z0-9.-]+\.[A-Za-z]{2,}\b
```

Matches valid email syntax but uses a negative lookahead to exclude gmail.com.

### find UK postcodes

```
\b[A-Z]{1,2}\d[A-Z\d]?\s?\d[A-Z]{2}\b
```

Matches the standard UK postcode format.

### match a hex color, with or without #

```
#?[0-9a-fA-F]{6}\b
```

Matches 6-character hex codes with an optional leading #.

### extract IPv4 addresses

```
\b(?:(?:25[0-5]|2[0-4]\d|[01]?\d\d?)\.){3}(?:25[0-5]|2[0-4]\d|[01]?\d\d?)\b
```

Matches valid IPv4 addresses with bounded octets (0-255).

## Frequently asked questions

### Which flavor of regex does this generate?

By default the output is PCRE-compatible and runs as-is in JavaScript (ECMAScript), Python, Go, Java, and most other modern regex engines. Some flavor-specific tokens — like lookbehind in older JS engines — will be flagged in the explanation.

### How do I use the generated regex in JavaScript?

Wrap the pattern in slashes with the flags after — for example /pattern/gi — or pass it as a string to new RegExp(pattern, 'gi'). Use String.prototype.match, matchAll, replace, or test depending on what you need.

### What do the flags mean?

g matches all occurrences (not just the first), i is case-insensitive, m makes ^ and $ match line boundaries instead of the whole string, and s lets . match newlines. The tool picks sensible defaults but you can edit them.

### Why does the explanation not match the regex exactly?

The token breakdown explains each meaningful piece — character classes, quantifiers, groups — in order. If the regex contains literal punctuation, it shows up as 'literal x' rather than as a separate token. If you spot a real mismatch, regenerate or refine the description.

### Can I use this for password validation?

You can, but consider whether you actually need a regex. Most password rules — minimum length, character class requirements — are clearer when written as a sequence of small checks. Regex is a great fit for extraction and matching, less so for boolean validation against many rules.

### Does the test panel save my pasted text?

No. The test panel runs entirely in your browser. Pasted text never leaves your device.

## References

- [Regular expressions guide](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_expressions) — MDN Web Docs. Reference for JavaScript regex syntax, flags, groups, and lookaround.
- [RegExp objects](https://tc39.es/ecma262/multipage/text-processing.html#sec-regexp-regular-expression-objects) — TC39. The ECMAScript specification text that defines how JavaScript engines evaluate patterns.
- [PCRE2 pattern syntax](https://www.pcre.org/current/doc/html/pcre2syntax.html) — PCRE. Syntax summary for the PCRE flavour used by PHP, nginx, and many command-line tools.

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- [Cron Expression Generator](https://generate.now/cron): Turn plain English into cron expressions. Or paste a cron expression and get a human-readable explanation.
- [JSON to TypeScript Types](https://generate.now/json-to-types): Paste JSON, get TypeScript interfaces, type aliases, Zod schemas, or Valibot schemas. Updates as you type.