RegexPlanet

What RegexPlanet is

RegexPlanet is a web service for checking regular expressions during development. It provides test pages for a wide selection of engines, including Java, Python, Bun, Go, Deno, Erlang, Haskell, MySQL, .NET, Node.js, Perl, PHP, PostgreSQL, Ruby, Rust, Swift, Tcl, XRegExp, and the browser. In the Java tester, you can enter a regex, a replacement, and several input strings, then add more inputs as needed. Options include case-insensitive matching, multiline mode, and Unicode-aware case folding. The home page has a field for entering a share code; RegexPlanet also directs users to Regex Zone to exchange expressions and find common patterns. A status page reports the condition of each engine and says each runs in its own instance. The service is free to the public and available on the web. Its maker cautions that malformed expressions may run indefinitely and that some engines or hosts may be open to denial-of-service attacks. The privacy policy says the site collects IP addresses, user agents, other browser-sent data, and form entries. It says data is not stored locally, while raw logs are held by its cloud provider, currently Google CloudRun.

Who it suits

RegexPlanet suits developers who want to check expressions against multiple regex engines in a web browser. It may also help people looking for example patterns through Regex Zone or a way to share expressions using share codes.

Limits

The service is provided free to the public. The maker warns that malformed expressions can run indefinitely and that some engines or hosts may be susceptible to denial-of-service attacks.

Getting started

1. Open https://www.regexplanet.com/ in a web browser.
2. Choose a regex test page for an available engine.
3. Enter a pattern and, where supported, provide replacement text and input strings.
4. Set any available engine options, then use the tester.
5. Enter a share code on the home page or visit Regex Zone to find and share patterns.

Verdict

Choose RegexPlanet if you need a free web-based place to compare regex behavior across its supported engines, especially with the Java tester’s input and matching controls. Consider the maker’s security warning and the stated collection of browser and form data before entering sensitive content.