Regex Tester & Visualizer — Live Match Highlighting, Token Breakdown
Test and debug regular expressions in real time. Paste your pattern and test string — matches highlight instantly with a per-token explanation breakdown. Supports all JS regex flags. 100% client-side.
Frequently Asked Questions
What regex flags does the tester support?
The tester supports all standard JavaScript regex flags: g (global — find all matches), i (case insensitive), m (multiline — ^ and $ match line starts/ends), and s (dotAll — dot matches newlines). Toggle any combination using the flag buttons below the pattern input.
How does the token breakdown work?
The tool parses your regex pattern character by character and identifies quantifiers, character classes, groups, anchors, escape sequences, and special characters. Each token is displayed with a plain-English description so you can understand or debug unfamiliar patterns without consulting documentation.
Does the tester support named capture groups?
Yes. Named capture groups using (?<name>…) syntax are parsed, displayed in the breakdown, and their matched values appear per-match in the Match Details table. This works with all modern browsers that support the ES2018 named capture group specification.