Highlight RegExp Matches
Visualize exactly what your Regular Expression matches in real-time.
Pattern & Settings
Statistics
/fox|quick/gi
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See Your Regex in Action
The Highlight RegExp Matches tool brings clarity to complex patterns. Regular expressions can be cryptic; by seeing exactly which characters are being captured in real-time, you can debug and refine your patterns with confidence.
How to Use
- Choose a preset or enter your custom regex pattern
- Toggle flags and pick a highlight color
- Paste or upload your text
- See matches highlighted instantly in real-time
- Download HTML to save the visual result
Common Use Cases
Pattern Debugging
See exactly what your regex matches. Catch over-matching or under-matching issues instantly with visual feedback.
Learning & Teaching
Experiment with quantifiers, character classes, and wildcards. Perfect for students or demonstrating regex concepts to teammates.
Presentations
Download as HTML with color highlighting. Share visual regex examples in documentation or training materials.
Common Uses
Debugging
Figure out why your regex is matching "too much" or grabbing the wrong characters.
Learning
Experiment with wildcards and quantifiers to see their immediate effect on text.
How it works
- Input: You provide the text and the regex pattern.
- Scan: We scan the text for all occurrences.
- Mark: We wrap every matching segment in a
<mark>tag with your chosen color.
Example
Frequently Asked Questions
Does it support lookaheads and advanced regex features?
Yes, we use the browser's native JavaScript regex engine, so advanced features like positive/negative lookaheads (?=...), lookbehinds, capture groups, and Unicode flags are fully supported. Test any ES6+ regex feature.
Can I replace the matches?
This tool is purely for visualization and testing. To replace matches, check out our 'Replace Text' tools or use a code editor. However, you can download the highlighted version as HTML to see visual results.
Can I change the highlight color?
Absolutely! Choose from 5 highlight colors: Yellow (default), Green, Blue, Pink, or Orange. The color picker is located in the Pattern & Settings panel. Your choice applies instantly to all matches.
Can I upload files to test patterns?
Yes! Click the Upload button in the Input Text header to load .txt or .md files. Great for testing regex patterns against log files, documents, or large text datasets.
How do I download the highlighted results?
Click the HTML button to download a complete HTML file with embedded styling that preserves the highlighting. Open it in any browser to see your matches highlighted. Also supports JSON export with pattern and statistics.
What's the difference between Total and Unique matches?
Total Matches counts every occurrence (e.g., 'cat' appears 5 times = 5 total). Unique Matches counts distinct values (e.g., 'cat', 'dog', 'cat' = 2 unique). Helps identify pattern coverage.
Why use this over a code editor's regex search?
Visual highlighting with customizable colors, real-time updates as you type, preset patterns for common use cases, statistics dashboard, and downloadable HTML output. Perfect for learning, debugging, or demonstrating regex to others.
Can I test case-insensitive patterns?
Yes! Toggle the 'i' (case-insensitive) flag button, or add 'i' to the flags field. With the 'i' flag, pattern 'hello' will match 'Hello', 'HELLO', and 'HeLLo'.
What are the preset patterns for?
The preset dropdown contains 6 common patterns: Email Addresses, URLs, Phone Numbers, Dates, Hashtags, and Numbers. Click any preset to instantly apply the pattern and correct flags, saving you time.
Is this useful for learning regex?
Extremely! Visual highlighting shows exactly what each part of your regex matches. Experiment with quantifiers (*, +, {2,5}), character classes ([a-z]), and wildcards (.) to see their immediate effect. Perfect for beginners and teaching.