Is my regex or test data uploaded anywhere?

No. Parsing, visualization, and matching all happen entirely in your browser via JavaScript — nothing you type is sent to a server, including by this site.

What regex flavor does it use?

JavaScript (ECMAScript) regular expression syntax, the same engine used by browsers and Node.js.

Can I build a pattern without typing regex syntax?

Yes — the visual editor lets you add and rearrange pattern elements directly on the diagram, and keeps the textual regex in sync as you go.

Regex Visualizer — Visual Regular Expression Editor

Visualize, build, and test regular expressions with a railroad-diagram editor. Runs entirely in your browser — nothing you type is ever uploaded.

Was this useful?

Related tools

Regex TesterCode

Test regex patterns with live matches.

Regex EscapeCode

Escape text so it can be safely used inside a regular expression.

Regex GeneratorCode

Generate regular expressions from common patterns like email, URL, IP, and phone.

Swagger Editor — OpenAPI & AsyncAPI EditorCode

Design, describe, and document OpenAPI and AsyncAPI specs with real-time validation and a live preview.

Ace Editor Playground — In-Browser Code EditorCode

Try the Ace code editor live with syntax highlighting for 45+ languages, 24 themes, and every editor setting.

Monaco Editor Playground — VS Code's Code EditorCode

Try Monaco Editor, the code editor that powers VS Code, with syntax highlighting, IntelliSense, and a live diff view for dozens of languages.

About Regex Visualizer — Visual Regular Expression Editor

Regex Visualizer turns a regular expression into an interactive railroad diagram, making its structure easy to follow at a glance instead of parsing dense pattern syntax by eye. Build and edit patterns visually, or type a regex directly and watch the diagram update, then test it live against sample strings. The build here is self-hosted directly from the regex-vis project's own source and runs entirely client-side: nothing you type is ever uploaded.

How to use

Type or paste a regular expression into the editor.
The railroad diagram updates automatically, showing each part of the pattern as a connected visual flow.
Click into the diagram to edit the pattern visually, or switch to the Test tab to try it against sample strings and see live matches.

Frequently asked questions

Is my regex or test data uploaded anywhere?: No. Parsing, visualization, and matching all happen entirely in your browser via JavaScript — nothing you type is sent to a server, including by this site.
What regex flavor does it use?: JavaScript (ECMAScript) regular expression syntax, the same engine used by browsers and Node.js.
Can I build a pattern without typing regex syntax?: Yes — the visual editor lets you add and rearrange pattern elements directly on the diagram, and keeps the textual regex in sync as you go.