Complete regular expression syntax reference with real-time test runner.
Execution runs 100% locally inside the browser sandbox using HTML5 Canvas, Web Cryptography Subtle API, and Web Workers. Zero egress.
Zero network latency. Operates completely offline with zero dependencies on third-party backend servers or cloud services.
Built according to official RFC specifications, cryptographic test vectors, and enterprise-grade data transformation standards.
Filter by Character Classes, Quantifiers, Anchors, or Lookarounds.
Click any token to instantly append it to the live regex test runner.
Verify real-time matches against sample text and copy the finalized pattern and flags.
Capturing groups (abc) store the matched substring in memory for backreferences and match extraction. Non-capturing groups (?:abc) group expressions logically without memory overhead.
Lookaheads assert whether a pattern is followed by specific characters without including those characters in the final match result.
Zero-egress companion tools in the Developer Tools suite
Format, validate, repair, and minify JSON data instantly.
Decode, verify claims, inspect headers, and check token expiry.
Test regex patterns with flags, group captures, and live matches.
Compare text or source code side-by-side with visual diffs.
