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TabBench

Regex Builder

Build a regular expression visually: add blocks such as digits, letters, text and groups, set how many times each repeats, and watch live matches. Exports to 8 languages.

Runs in your browser. Nothing you add is uploaded.

What the Regex Builder does

Regular expressions are powerful and famously hard to read. This builder lets you assemble one from plain-language blocks instead: the text “https://”, one or more digits, between two and four letters, one of cat, dog or bird, a group with a name. As you add blocks the expression, a plain-English reading of it and the highlighted matches in your test text all update live. Text is escaped for you, repeats are wrapped correctly, and the finished expression can be copied or exported as code for eight languages.

How to build a regular expression

  1. Start from one of the examples, such as email, date or phone number, or choose Clear all to begin with nothing.
  2. Use “Add a block” to add pieces in the order they should appear: text, digits, letters, a set of characters, options, a group, or an anchor such as the start of the text.
  3. For each block set how many times it should repeat: once, optional, one or more, exactly N, or between N and M.
  4. Paste text into “Try it” to see the matches highlighted. Turn the flags on or off: find all, ignore case, multiline.
  5. Copy the expression, pick a language to export it as code, or open it in the Regex Tester to go further.

The Regex Builder runs entirely in your browser — nothing you enter is uploaded, stored, or logged.

When to use it

Validating form input

Build a pattern for a postcode, a mobile number, a PAN or a username, and test it against good and bad examples before it goes into your code.

Extracting data from text

Pull dates, prices, IDs or hashtags out of logs, emails and documents with groups that capture just the part you want.

Learning regular expressions

See how each block becomes syntax, and read the English description of the result, to learn the notation by doing.

Good to know

  • Anchors ^ and $ make a pattern match the whole text; leave them out to find matches inside longer text.
  • “As few as possible” (lazy) repeats stop at the first possible place, which matters for things like quoted strings.
  • Use a named group so your code can read results by name instead of by number.
  • Look-arounds check the surroundings without including them in the match, which is useful for prices or numbers next to units.
  • Test with both text that should match and text that should not.

Frequently asked questions

Do I need to know regular expressions to use it?

No. Each block is something you can say in words, such as “2 to 4 digits” or “the text https://”. The generated expression and its plain-English reading let you pick up the syntax as you go.

Why is my text escaped with backslashes?

Characters such as . ? ( ) + * [ ] have special meaning in regular expressions. The Text block escapes them so they match literally. You never have to add the backslashes yourself.

Can I keep editing in the Regex Tester?

Yes. “Open in the Regex Tester” carries the pattern, flags and your test text across, where you can also test replace and split, and read the full explanation.

What regex flavour does it produce?

JavaScript's. Most of it works unchanged in other languages; the export panel rewrites named groups, quoting and flags for each language and lists the features that differ, such as look-behind in Go and Rust.

Can it read an existing regular expression back into blocks?

No. The builder creates expressions from blocks. To understand an existing one, paste it into the Regex Tester, which explains every part in plain English.

Is my test text kept?

No. It stays in your browser. Nothing is sent or saved, apart from the flags you last chose.

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