RegEx Visualizer & Explainer vs RegexPlanet

RegEx Visualizer & Explainer is a browser tool for testing and debugging regular expressions. As a pattern is entered, it highlights matches and shows match and capture-group details. The tool explains individual tokens and provides a step-by-step debugger. Test mode checks pattern matches, Replace mode previews substitutions, and Diff mode compares two patterns. Test cases, presets, a cheatsheet, and browser history are also included. Matching uses the browser’s JavaScript RegExp engine and supports its regex flags. Testing runs in the browser; the page says content stays on the user’s device unless they copy or download a file. The tool runs on the web without installation or an account, and the Free plan costs nothing. It does not provide a multi-language code export panel, so patterns should be retested for differences in a target language. ToolsViewer describes its collection as intended for developers, students, designers, and other professionals. Support requests can be sent by email, with replies targeted within a few business days.

RegexPlanet is a free web service for testing regular expressions during development. It offers separate test pages for engines including Java, Python, Bun, Go, Deno, Erlang, Haskell, MySQL, .NET, Node.js, Perl, PHP, PostgreSQL, Ruby, Rust, Swift, Tcl, XRegExp, and the browser. The Java tester accepts a pattern, replacement, and multiple input strings, with a control for adding more inputs. Options include case-insensitive matching, multiline mode, and Unicode-aware case folding. The home page provides a field for share codes, and the site directs users to Regex Zone for sharing expressions and finding patterns. A status page reports engine status and says each engine runs separately. RegexPlanet warns that malformed expressions may run indefinitely and that some engines or hosts may face denial-of-service attacks. Its privacy policy describes collection of IP addresses, browser data, and form entries; raw logs are stored by Google CloudRun. The service is offered as-is and as-available.