Regex Tester
Test regular expressions with live match highlighting and capture group table.
Tool code processes selected files and entered content in your browser and does not submit them to a TOOLGRID processing endpoint. TOOLGRID measures tool usage, not the content you enter.
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Browser-basedWhat this tool does
Build and test regex patterns with flags, highlighted matches, and capture group inspection.
Capture groups appear in a table below, and preset patterns let you start quickly.
What you can do with this tool
Test an email, slug, SKU, or identifier pattern against realistic sample text before copying it into code or form validation.
Use the match table to confirm that each group captures the exact token your parser, replacement, or extraction script expects.
Toggle global, case-insensitive, multiline, and dotAll flags to see how the same pattern changes across common JavaScript regex modes.
What to check before relying on the result
- Performance and maximum practical input size depend on browser memory, device speed, and the structure of the input.
- Review the generated result before replacing or publishing an original file.
How to use
- 1
Enter or choose a preset pattern.
- 2
Set flags (g, i, m, s) as needed.
- 3
Paste test text and see matches highlighted with cycling colors.
Use Cases
Test an email, slug, SKU, or identifier pattern against realistic sample text before copying it into code or form validation.
Use the match table to confirm that each group captures the exact token your parser, replacement, or extraction script expects.
Toggle global, case-insensitive, multiline, and dotAll flags to see how the same pattern changes across common JavaScript regex modes.
Tips & Tricks
If the input parser reports an error, fix the source value first instead of copying a partial result into code, config, or documentation.
Characters like ., ?, +, *, [, ], (, and ) have special regex meaning. Escape them with a backslash when you want to match the literal character.
The tool runs in your browser, but you should still avoid pasting long-lived production secrets into any shared or screen-recorded session.
A pattern can match part of a value unless you anchor it. Add ^ at the start and $ at the end when a full field must match, such as a complete slug or ID.
FAQ
What flags are supported?
g (global), i (case-insensitive), m (multiline), and s (dotAll).
How many matches does it find?
Up to 500 matches per test to keep the UI responsive.
Does it show named capture groups?
It shows numbered capture groups. Named groups are shown by their position.
Useful next steps
Open a nearby browser tool when you need to validate, convert, or reuse the result.