RegexToolbox

Regular expressions are one of those things most developers look up every time. RegexToolbox lets you skip the syntax. Type what you want in plain words, up to 200 characters, such as extract webpage URLs or match dates in yyyy-mm-dd format, and the AI returns a regex you can test against your own text on the same page. Example prompts fill the box with one click.

The site is upfront that AI output is for reference and should be verified before use. That matters with regex, where a pattern that looks right can still miss edge cases, so the built-in tester is the useful part.

If you'd rather start from something known, a table lists ready-to-copy patterns with examples: URLs, IPv4 addresses, email addresses, HTML tags, strong passwords, dates, 24-hour times, hex colors, usernames and integers. Several entries target Chinese text, such as Chinese characters, full-width punctuation, mainland mobile and landline numbers, postal codes and ID numbers. Any of them can be imported into the AI editor to adjust.

The learning section has a beginner's guide, a quick syntax cheat sheet, practical techniques for extracting, replacing and validating text, and common interview questions, plus blog posts such as one on lookahead.

The homepage states that generated regexes are publicly visible and appear among shared examples. The privacy policy says inputs, patterns and outputs are processed to provide the service, asks users not to enter sensitive personal data, and lists hosting, analytics and support providers in general terms. It's free with no paid tier. Keep real customer data, internal URLs or anything confidential out of your prompts, and test patterns with dummy text.