Regex Tester
Build and debug JavaScript regular expressions with live feedback. Toggle flags (g, i, m, s, u, y), see every match highlighted in your test string, inspect numbered and named capture groups in a table, and switch to Replace mode for a live preview of the substituted output. Fully client-side, uses your browser's native RegExp engine so behavior matches what you'll see in production JS code.
| # | Index | Match | Groups |
|---|---|---|---|
| 1 | 8 | alice@example.com | $1: alice $2: example.com |
| 2 | 29 | bob@test.io | $1: bob $2: test.io |
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About Regex Tester
Live regex testing with match highlighting, capture group tables, and replace preview. A browser-based alternative to regex101 for JavaScript regex. This tool runs entirely in your browser — no data is sent to any server. Your content stays private and secure. MarkdownMe provides free, fast, and reliable Markdown tools for developers, writers, and anyone who works with Markdown.