Developer Tools
Regex Tester
Write, test, and debug regular expressions with instant feedback. See all matches highlighted in the test string, with detailed match groups and index positions. Supports all standard JavaScript regex flags.
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Type your regular expression in the regex field
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Toggle flags using the chip buttons (global, case insensitive, etc.)
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Type or paste your test string
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Watch matches highlight in real time
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Review match details including captured groups and positions
🔎 Regex Tester
Test regular expressions in real time. See matches highlighted, capture groups, and match details instantly.
Regular Expression
/
/
g — global
i — case insensitive
m — multiline
s — dot all
💡 Pro Tips & Best Practices
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Always enable the 'g' flag when you want to find all matches, not just the first one.
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The 'i' flag makes your regex case-insensitive — useful for matching user input.
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Use \d for digits, \w for word characters, \s for whitespace to keep patterns readable.
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Use () to create capture groups — the matched group content appears in the match details panel.
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Use ^ to match the start of a string and $ to match the end — combine for exact full-string matching.
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Test edge cases: empty strings, special characters, and very long inputs.
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Regex lookahead (?=) and lookbehind (?<=) let you match based on context without capturing it.