RegexPlanet
RegexPlanet is a free website for testing regular expressions during development.
What RegexPlanet is
RegexPlanet is a free website for testing regular expressions during development. It provides test pages for engines including Java, Python, Bun, and Go, along with options such as Deno, Erlang, Haskell, MySQL, .NET, Node.js, Perl, PHP, PostgreSQL, Ruby, Rust, Swift, Tcl, XRegExp, and the browser. The Java tester accepts a regular expression, a replacement, and multiple input strings, and lets users add more inputs. It also exposes settings for case-insensitive matching, multiline mode, and Unicode-aware case folding. The home page includes a field for share codes, which it describes as a way to share regexes, and points users to Regex Zone for sharing patterns and finding common expressions. A status page reports engine availability and says each engine runs in a separate instance. The maker cautions that malformed patterns may run indefinitely and that some engines or hosts may be vulnerable to denial-of-service attacks. The privacy policy says the site collects IP addresses, browser-sent data, and form entries; raw logs are stored by its cloud provider, currently Google CloudRun. The service is offered as-is and as-available, without a warranty of uninterrupted or error-free availability.
Good
- Provides testers for many regex engines.
- Java tester accepts multiple input strings.
- Includes matching options such as multiline mode.
- Offers share codes and points to Regex Zone.
Watch out
- Malformed expressions may run indefinitely.
- Some engines or hosts may face denial-of-service risk.
- The site collects IP addresses and form entries.
- Availability and error-free operation are not guaranteed.
Who it suits
It suits developers who want a browser-based place to check regular expressions against one or more input strings. Those comparing behavior across engines may find its range of test pages useful.
Verdict
RegexPlanet offers a free web-based way to test patterns across multiple engines, with the Java tester providing several useful controls. Be mindful of the stated execution risks and data collection.
Plans and prices
From RegexPlanet's own pricing page, checked 8 Oct 2026.
| Plan | Price | What it gives you |
|---|---|---|
| Free public service | Free | Website for testing regular expressions · provided free to the public |
The facts
Each one read from RegexPlanet's own pages, with the date it was checked.
What it does
- Data storage
- The privacy policy says the maker does not store data locally and that raw log files are stored by its cloud provider, currently Google CloudRun.checked 8 Oct 2026
- Engine options
- The Java tester exposes engine options such as case-insensitive matching, multiline mode, and Unicode-aware case folding.checked 8 Oct 2026
- Engine status
- A status page reports the status of each engine and says each engine runs in a separate instance.checked 8 Oct 2026
- Open source repository
- The maker's GitHub repository describes a next-generation version and lists the GNU Affero General Public License v3.0 or later.checked 8 Oct 2026
- Privacy data
- The privacy policy says the site collects IP addresses, user agents, other browser-sent data, and anything entered into forms.checked 8 Oct 2026
- Purpose
- RegexPlanet is a website for testing regular expressions during development.checked 8 Oct 2026
- Regex community
- The site directs users to Regex Zone to share regular expressions and find common patterns.checked 8 Oct 2026
- Regex engines
- The site provides regex test pages for engines including Java, Python, Bun, and Go.checked 8 Oct 2026
- Security limitation
- The maker warns that badly formed regular expressions can run indefinitely and that some engines or hosts may be susceptible to denial-of-service attacks.checked 8 Oct 2026
- Share codes
- The home page describes share codes as a way to share regexes and provides a field for entering one.checked 8 Oct 2026
- Support
- The site provides a contact form for questions and inquiries.checked 8 Oct 2026
- Terms and availability
- The terms describe the service as provided as-is and as-available, without a warranty that it will be available, uninterrupted, secure, or error-free.checked 8 Oct 2026
- Test inputs
- The Java tester has fields for a regular expression, replacement, and multiple input strings, with a control to add more inputs.checked 8 Oct 2026
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