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Regular Expression Railroad Visualizer

100% Client-Side Privacy: AST syntax parsing, vector layout, and test matching execute strictly inside your browser. No data leaves your machine.
Zero Server Latency
//gi
Valid Syntax•2 Capturing Groups•12 Parsed AST Nodes
Click or hover diagram elements to trace syntax branches
Diagram
100%
Group #11+ times[a-zA-Z0-9._%+-]One of"@"literalGroup #21+ times[a-zA-Z0-9.-]One of"."literal2+ times[a-zA-Z]One of
Syntax Elements:
Literal
Character Class
Escape Code
Wildcard (.)
Anchor (^ / $)
Capture Group
Quantifier Loop

What is a Regular Expression Railroad Diagram?

A Railroad Diagram (also known as a syntax diagram) represents the grammatical flow of a regular expression as a network of railway tracks. Execution begins at the green entrance switch on the left and travels continuously along the rails to the red termination marker on the right. Diverging paths illustrate alternate choices (|), loops looping backwards depict repeated characters (+, *), and elevated bypass arches indicate optional segments (?).

Trace Complex Logic Visually

Forget deciphering tangled chains of nested brackets. Visual syntax rails allow developers to instantly spot unhandled branches, greedy backtracking traps, or misplaced group boundaries.

Zero Server Transmission

In line with ToolsAA's Privacy First Architecture, all regex lexing, AST transformation, vector layout computation, and test matching execute 100% inside your local web browser.

Vector SVG Export Ready

Need visual documentation for team pull requests, API specifications, or system architecture guides? Export crystal-clear SVG diagrams with a single click.