When to use regex tester
A small test string can clarify whether a pattern captures the intended text. Enter the expression without surrounding slashes and choose JavaScript flags. Matches include their index and capture groups. Execution runs in a separate worker with a time limit, so an expensive expression can be stopped without freezing the main interface.
How it works
- Enter a pattern and flags.
- Paste a sample string.
- Run the test and inspect matches and groups.
Try this example
Order A123 costs 42 dollars. Order B456 costs 18 dollars.
Before you export or rely on the result
JavaScript regular expressions differ from PCRE and other engines. Tests stop after one second or 1,000 matches, and input is limited to 100,000 characters.
Does this tool upload my input?
No. This tool processes input in your browser. Optional advertisements are separate third-party content and load only when you allow ads. See the privacy notice for hosting logs and advertising details.
Can I use the result without creating an account?
Yes. Regex Tester is free to use without an account. Review the result against the limits above and the requirements of the app or document where you plan to use it.