About this utility
How to use Regex Tester
Test a JavaScript regular expression and inspect matches and capture groups.
What to provide
Enter the pattern without surrounding slashes.
Matches are located in this text without executing replacement code.
- Paste, type, or drag and drop a supported text file into the input area.
- Place the second value or file in the adjacent panel. Sensitive fields are masked by default.
- Choose the options that match your intended result.
- Select “Run tool” or press Ctrl/Command + Enter, then copy, download, or move the result back into the first input for another pass.
Use “Swap inputs” to reverse the comparison without copying either value.
What the result means
Match text, indexes, and capture groups.
Privacy and safety
This utility is loaded as browser code and processes your input only in this tab. OmniCastConverter has no upload endpoint and never stores your content, filenames, tokens, or secrets. Generated markup and code are shown as inert text and are never executed.
Limitations
- Patterns are capped at 500 characters and text at 100,000 characters. Matching runs in a disposable local worker with a two-second safety limit, so pathological expressions cannot freeze the interface.
Try the included example
Select “Load example” at any time to restore this tested sample.
([\w.+-]+)@([\w.-]+)Contact ada@example.com or grace@example.org.