Regex Tester
Test JavaScript regular expressions with flags, matches and capture groups.
Instructions: Regex Tester
Follow these steps to get a reliable result without unnecessary setup.
- 1
Enter a JavaScript regular-expression pattern without surrounding /slashes/.
- 2
Choose the options in Regex Tester that match your intended output, such as units, format, mode, range or quality when those controls are available.
- 3
Run Regex Tester and review the displayed result, preview or validation message before proceeding.
- 4
Validate the output in the context where you will use it, especially when the source data is incomplete or uses an unsupported syntax variant.
- 5
Use the available reset, copy or download action in Regex Tester when you are satisfied with the result; only actions supported by this tool are shown.
About this tool: Regex Tester
Enter a pattern, flags and test text to validate the expression, highlight matches, count results and inspect capture groups without executing external code.
It is intended for development and data-cleanup workflows, with errors kept inside the interface so malformed input does not crash the page.
Regex Tester is presented in the shared NexterHub tool layout so the working controls stay near the top while the method, example, limitations and related utilities remain available below the result.
How it works
NexterHub constructs a JavaScript RegExp and uses repeated exec calls for match collection. A global scan flag is added internally when needed so all matches can be listed while preserving the user-selected matching behavior as closely as practical.
Practical example
Pattern \b[A-Z][a-z]+\b with text “Alice met Bob” returns Alice and Bob as two matches.
Important notes
Validate the output in the context where you will use it, especially when the source data is incomplete or uses an unsupported syntax variant.
Privacy & processing
The primary formatting, parsing, encoding or conversion logic for this tool runs in the browser in the current build.
Frequently asked questions
What does Regex Tester do?
Test JavaScript regular expressions with flags, matches and capture groups.
How do I use Regex Tester?
Start with the main input step: Enter a JavaScript regular-expression pattern without surrounding /slashes/. Then choose any relevant options, run the tool and review the result.
How does Regex Tester calculate or process the result?
NexterHub constructs a JavaScript RegExp and uses repeated exec calls for match collection. A global scan flag is added internally when needed so all matches can be listed while preserving the user-selected matching behavior as closely as practical.
What should I check before using a result from Regex Tester?
Validate the output in the context where you will use it, especially when the source data is incomplete or uses an unsupported syntax variant.
Does Regex Tester send my input to a NexterHub server?
The primary formatting, parsing, encoding or conversion logic for this tool runs in the browser in the current build.
Can I use Regex Tester on a phone or tablet?
Yes. Regex Tester uses the responsive NexterHub tool layout, so controls and results adapt to smaller touch screens.