Regex Capture Group Reference
Find named and numbered capture groups in a regular expression. See where each group starts and how it is used.
How do I find capture groups in a regular expression?
Paste a JavaScript regular expression to list its named and numbered groups. The report shows their locations and references. The tool reads the pattern without running it against text.
Your result
A little clarity, right here.
Start with your own content or load the example. Your result will appear here.
Three simple steps
How to use Regex Capture Group Reference
Choose your input and adjust the options.
Review the preview and run the tool.
Download the result and keep your original.
Common questions
Good to know
Understand the result.
Keep the original.
Is this tool free, and are my files uploaded?
This tool is free with no account required. The work happens in your browser. Your input and files are not sent to a processing server.
What are the limits and details?
Use a JavaScript regex literal including its slashes and flags, up to 10,000 characters. The syntax tree is capped for preview. Parsing does not establish that a pattern is fast or safe to execute on arbitrary text.
Limits: 500,000 characters per text field; files up to 20 MB each, 10 files and 50 MB total. Processing stops after 30 seconds.