Developer
Regex Tester
Test a JavaScript regular expression and inspect all matches.
What this tool is for
Regex Tester helps you test JavaScript regular expressions against sample text. Processing happens in the current browser session, so the normal workflow does not require uploading the text to BiNotePads.
How to use Regex Tester
- Enter or paste the source data and keep an untouched copy when the order or formatting matters.
- Choose the available options, then select Process.
- Review the entire result before copying, downloading, publishing or importing it elsewhere.
Find a word rather than a fragment
Try this small sample before using your own text.
Sample input or options
Input: cat scatter cat Pattern: \bcat\b Flags: g
What to check in the result
Two matches: cat at indexes 0 and 12.
Before you use the output
The pattern uses JavaScript regular-expression rules and is entered without surrounding slash delimiters. The g flag returns multiple matches; i adds case-insensitive matching. Word boundaries have language-specific limitations. Large inputs and patterns with heavy backtracking can freeze the page, so start small. A successful test on one example does not establish a reliable production validator.
Read the complete workflow guide
Common uses
- Learning pattern syntax
- Testing validation ideas
- Finding structured text
Limits and accuracy
Regular-expression behavior differs between programming languages and unsafe patterns can be slow. Keep the original text, verify important results and use a specialized application when a task carries legal, security, financial or production risk.
Privacy and safety
This tool is intended for ordinary text and development samples. Do not paste passwords, authentication tokens, private keys, payment information, medical records or confidential client data into a general-purpose web page. Closing or refreshing the page can remove unsaved input.
Frequently asked questions
Does Regex Tester upload my text?
No. The tool is designed to process input in your browser. Avoid pasting passwords, private keys or highly sensitive records into any ordinary web tool.
Can I use the result commercially?
You can use the transformed text in your own work, but you remain responsible for checking accuracy, rights, formatting and any platform-specific requirements.
Why can the result differ from another application?
Regular-expression behavior differs between programming languages and unsafe patterns can be slow. Different applications can use different parsing, language and encoding rules.