Regex Tester
Test and debug regular expressions with match highlighting, capture groups, and ReDoS protection.
100% Client-Side · No Upload
Loading tool…
What is Regex Tester?
Regex Tester is an editor for writing and debugging regular expressions. With real-time match highlighting, capture group details, and character checklists, it helps you write accurate search strings.
How to use Regex Tester?
1
Input the search pattern regex in the pattern box.
2
Paste your test text in the body workspace.
3
Matches highlight instantly in green, and details update in the sidebar.
4
Hover over highlights to inspect captured groups and matching segments.
Interactive Example
Matching email regexTEXT
Input / Sample Source
Pattern: /[a-z]+@site\.com/
Text: contact saish@site.comOutput / Result
Match found: "saish@site.com" at index 14.Benefits & Features
✓
Real-Time HighlightsInstant matching highlights as you type.
✓
Capturing Group TreeDisplays capture group breakdowns and indexes.
✓
Regex ChecklistHelpful sidebar displaying common patterns, flags, and rules.
✓
Multi-Flag ConfigurationToggle global (`g`), multiline (`m`), and case-insensitive (`i`) options.