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Regex Tester

100% Client-Side

Test JavaScript regular expressions with real-time match highlighting, group capturing, error debugging, and common preset patterns.

Regular Expression

Preset:

/ /

Global (g) Case-insensitive (i) Multiline (m) DotAll (s)

Test String

Highlighted Matches 0 matches found

How to Use Regex Tester

Enter Pattern & Flags

Type your regular expression pattern and toggle flags (g, i, m, s).

Paste Test Content

Enter the candidate text strings you want to match against.

Inspect Highlighted Matches

Review matching segments, match counts, and captured sub-groups.

✓ Visual Match Highlighting

Live yellow highlights show exactly where expressions trigger on test text.

✓ Pattern Presets

One-click presets for emails, URLs, dates, phone numbers, and IPv4 addresses.

✓ Capture Groups Inspector

Displays captured parenthetical sub-groups and their indices.

🔒 Complete Client-Side Isolation

This tool runs entirely in your local browser runtime. No logs, analytics tracking, or remote server transmissions occur.

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