Regex builder and tester
Build a regular expression from blocks, watch it match as you go, then copy it out for JavaScript, Python or PCRE.
- In
- text
- Out
- REGEX
Builder
Tester
Capture groups
Examples
One-click starters. Pick a pattern, tweak the blocks, and copy.
Related
Questions
Do I need to know regex syntax?
No. Each block has a plain name and a short hint. You pick blocks, the syntax is written for you; a pasted expression is taken apart into the same blocks.
Which regex flavors are supported?
JavaScript, Python, and PCRE. Flavor-specific details like named group syntax are translated for you on copy.
Is my test text sent anywhere?
No. Everything runs locally in your browser. There is no backend.
Can I save my patterns?
Not on the page. Copy the expression and paste it back into the import field later — it becomes blocks again.
Why do I see a different result in my code?
Most often this is a flag or flavor mismatch. Make sure the dialect selector matches the language you are copying into, and double-check flags like case-insensitive or multiline.