How to use Regex Tester
- Enter a JavaScript regular expression without slash delimiters, such as \d+, and add flags such as g or i in the flags field.
- Paste a small sample into the test-text area and select Find matches safely.
- Review match positions, numbered or named capture groups, and the JSON report. Simplify patterns that exceed the execution limit.
What this tool does
Patterns run with an execution limit; other regex dialects may differ.
Example
Use pattern (\d{4})-(\d{2}) with flag g and sample 2024-03 2025-11 to find two year-month matches and inspect both capture groups.
Frequently asked questions
Which regular-expression flavor is supported?
This tester uses the JavaScript RegExp engine. Patterns written for PCRE, Python, or another engine may behave differently.
What happens if a pattern takes too long?
Matching runs in a worker with an execution limit. If it exceeds the limit, the worker is stopped and the page reports an error.
Privacy
Your input is processed in your browser. This version does not send document content to a conversion server and includes no advertising or analytics scripts. Loading the website requires a network connection.
Operator: Francescco Pernice Botta. Contact: klabindustries.hq@gmail.com.
Terms
Use this tool only with content you are allowed to process. Check the result before relying on it.
Contact
Operator: Francescco Pernice Botta. Contact: klabindustries.hq@gmail.com.