Free Regex Prompt Generator
Describe the pattern you want to match and generate a prompt that gets AI to write the exact regular expression — explained part by part, with test cases so you can trust it.
Your prompt
How to use the Regex Generator
- Describe in plain English what you want to match, validate or extract.
- Pick your regex flavor and give a few matching / non-matching examples.
- Click Generate Prompt and run it in ChatGPT, Claude or Gemini.
- Test the regex against your examples before shipping it.
Get a regex you can actually trust
Regular expressions are easy to get subtly wrong — a pattern that looks right can quietly miss edge cases or match too much. This generator builds a prompt that returns the pattern with a part-by-part explanation and concrete test cases, so you can verify it does exactly what you need instead of pasting an opaque string and hoping.
Syntax differs between languages, so you pick your flavor — JavaScript, Python, PCRE, Java, .NET, Go and more — and the prompt asks for valid syntax and the right flags for your environment.
Give it examples
The single biggest quality boost is examples. A handful of strings that should match and a handful that shouldn't turns a guess into a spec — the AI can test its own pattern against them and correct itself. Always run those examples yourself before deploying the regex.