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.
- No TOOLGRID input upload
- No account
- Review before copy
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What this tool does
Build and test regex patterns with flags, highlighted matches, and capture group inspection.
Regex Tester highlights all matches in real time as you type your pattern.
Capture groups appear in a table below, and preset patterns let you start quickly.
Where this tool earns its place
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.
Open a nearby browser tool when you need to validate, convert, or reuse the result.
How to use
01Use 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
- 01Validate before copying
If the input parser reports an error, fix the source value first instead of copying a partial result into code, config, or documentation.
- 02Escape literal punctuation
Characters like ., ?, +, *, [, ], (, and ) have special regex meaning. Escape them with a backslash when you want to match the literal character.
- 03Keep secrets local
The tool runs in your browser, but you should still avoid pasting long-lived production secrets into any shared or screen-recorded session.
- 04Use anchors when you need the whole string
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
02What 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.