Regex Explainer

See a regex parsed into an AST tree with token-by-token descriptions.

Free & unlimited

Pattern

Pattern preview

^[\w.-]+@[\w.-]+\.[a-zA-Z]{2,}$

AST

^AnchorStart of string (or line in multiline mode)

[\w.-]+CharacterClassAny character in: \w.-, 1 or more (greedy)

@LiteralLiteral character "@"

[\w.-]+CharacterClassAny character in: \w.-, 1 or more (greedy)

\.EscapeLiteral .

[a-zA-Z]{2,}CharacterClassAny character in: a-zA-Z, 2 or more times

$AnchorEnd of string (or line in multiline mode)

Hover a node to highlight the matching portion of the pattern above.

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About this tool

1
Enter a regex pattern
Paste or type any regular expression into the input field.
2
Read the explanation
Each part of the regex is broken down into plain English with color-coded segments.
3
Test with sample text
Enter test strings to see which parts match and which groups are captured.
4
Explore the visual diagram
View a railroad diagram showing the regex flow from start to end.

Hover over any part of the regex to see its specific explanation highlighted.
Capture groups are numbered and color-coded to show which part of the match they extract.
Use the test panel to verify edge cases like empty strings, special characters, and Unicode.
Click on explanation segments to jump to the corresponding part of the regex.

Understand a complex regex found in a codebase you inherited
Debug why a regex is matching unexpected strings or missing valid ones
Learn regex syntax by seeing plain English explanations of each token
Document a regex by generating a human-readable description to add as a code comment