Regex Tester (JavaScript)
Free JavaScript regex tester with live match highlighting and replace. Runs in your browser.
100% runs in your browser — no upload, no trackingHow to use
Type a pattern and flags, paste your test text, then click Test. Add a replacement string to see the substituted result.
Example
Pattern: \d+\nText: abc123def456\nMatches: 123, 456
FAQ
Is my data uploaded to a server?
No. Every tool runs entirely in your browser. Your input never leaves your device.
Is this tool free?
Yes, all DevToolbox tools are free to use with no account required.
Does it work on mobile?
Yes, the interface is mobile-friendly and responsive.
How accurate is the conversion?
We use standard, well-tested algorithms (Web Crypto, Intl, DOMParser). Results match common reference tools.