Regex Generator for Common Patterns

Writing a regular expression from scratch is slow and easy to get subtly wrong. This generator gives you a tested pattern for the things developers match most often — emails, URLs, IPv4 addresses, dates, times, phone numbers, UUIDs, hex colours — or builds one from your own exact text or list of words, escaping the special characters for you. You also get a code snippet in the language you use and a live test against your own sample text.

How to use this tool

1. Pick what you want to match, or choose "Exact text" / "Any of these words" and type your text.
2. Choose Find to pull matches out of longer text, or Validate to check that a whole value has the right format.
3. Tick "Ignore upper / lower case" if capitalisation should not matter.
4. Press Calculate. Pick your language and copy the code; paste some real data into the test box to confirm it behaves as you expect.

Formula

Find mode: boundary + pattern + boundary (e.g. \b…\b). Validate mode: ^pattern$.

Boundaries such as \b or (?<!\d) stop a match starting or ending in the middle of a longer word or number. In validate mode the code uses each language's whole-string check (fullmatch in Python, matches() in Java, \z in .NET, the D modifier in PHP) so a trailing newline cannot slip through. Calculation runs in a worker and stops after two seconds.

Example

With Email address in find mode the pattern is \b[A-Za-z0-9._%+-]+@[A-Za-z0-9.-]+\.[A-Za-z]{2,}\b. On the text "Write to ann@example.com or bob.smith@mail.co.uk, not to bob@localhost." it finds 2 matches: ann@example.com and bob.smith@mail.co.uk. bob@localhost is skipped because it has no dot-and-letters ending such as .com.