Regex Explainer
Paste any regular expression and get a plain-English breakdown of every part, including character classes, quantifiers, anchors, groups, lookaheads, and flags.
Enter a regular expression above to see a detailed explanation
Regex Explainer
Paste any regular expression and get a plain-English breakdown of every part, including character classes, quantifiers, anchors, groups, lookaheads, and flags.
Features
- Breaks down any regular expression into individual tokens with plain-English descriptions
- Supports character classes, shorthand classes (\d, \w, \s), quantifiers, anchors, and alternation
- Explains groups including capturing, non-capturing, named groups, lookaheads, and lookbehinds
- Recognizes and explains all standard regex flags (g, i, m, s, u, y)
How to use
- Type or paste a regular expression into the input field, or click Sample to load an example email regex.
- Optionally enter flags (such as g, i, or m) in the flags field.
- Read the breakdown below: each token in the regex is shown alongside its plain-English explanation.
Tips & Best Practices
- You can paste text directly from any source — formatting will be preserved.
- Use the clear button to start fresh without refreshing the page.
- Large text inputs are supported but may take slightly longer to process.
- Copy the output directly to your code editor or document.
- All transformations happen instantly in your browser with no server roundtrip.
FAQ
What regex features are supported?
The tool explains character classes, shorthand classes (\d, \w, \s), quantifiers (*, +, ?, {n,m}), anchors (^, $), groups (capturing, non-capturing, named), lookaheads, lookbehinds, alternation, escape sequences, and all standard flags.
Does it validate the regex?
Yes. The tool attempts to construct the regex and will display an error message if the pattern is invalid.
Is my data sent to a server?
No. All parsing and explanation happens entirely in your browser. Your regex patterns never leave your device.
Can it explain complex nested groups?
The tool parses the outermost groups and explains their type (capturing, non-capturing, lookahead, etc.) along with their content. Deeply nested patterns are displayed as a whole group.
What flags are recognized?
The tool recognizes g (global), i (case-insensitive), m (multiline), s (dotall), u (unicode), y (sticky), d (has-indices), and v (unicode sets).