Browser-only regex testing

Online Regex Tester

Test JavaScript regular expressions with live match highlighting, capture group breakdowns, and instant replace previews.

Live highlightCapture groupsReplace preview

Private

Everything stays in your browser. No uploads, no logging, no servers.

Builder

Craft your expression.

Regex pattern

Flags

/pattern/flags

Global gFind all matches, not just the firstCase-insensitive iIgnore case differencesMultiline mTreat ^ and $ as line anchorsDotAll sAllow . to match newlinesUnicode uUse Unicode code pointsSticky yMatch from lastIndex only

Example library

Test string

Paste or load data.

Regex runs in your browser. Large inputs can take a moment to render.

Highlight

Live match preview.

Enter a pattern and test string to see highlights.

Results

Match summary.

Matches

Unique

Groups

Frequently Asked Questions

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