regex.ai

regex.ai builds regular expressions from examples. You paste text and highlight the strings you want to match, and several AI agents each propose an expression with a preview of what it matches.

The editor accepts up to 4,000 characters and shows each agent's pattern side by side, so you can compare how closely they capture your highlights. It comes from Liberty Labs and has documentation and a learning section. The site footer shows 2023, so development may be slow.