⚙️ WasmTools

Regular Expression Tester Online

Free online regex tester: run a regular expression against your text and list every match with positions. Rust regex engine in WebAssembly — 100% local.

Loading WebAssembly engine…

Use it in your terminal (or let an AI agent run it)

This tool also ships as a command-line version in the wasm-tools-cli npm package — the exact same engine as this page, running locally on your machine.

echo 'abc 123' | npx wasm-tools-cli regex test '[0-9]+'
🔒 Runs entirely in your browser — your files never leave your device.

About Regex Tester

Regex Tester is a free online data tool that runs entirely in your browser. There is nothing to install and no account to create: open the page, use the tool, and download the result. Because all processing happens locally on your device (via WebAssembly), your files and text are never uploaded to any server.

How to use Regex Tester

  1. Paste or type your content into the input box.
  2. Choose the operation (and any options) and click the corresponding button.
  3. Copy the result or download it as a file.

Frequently asked questions

Is Regex Tester really free?

Yes — Regex Tester is completely free, with no account, no watermark, and no usage limits. It runs entirely in your browser.

Are my files uploaded to a server?

No. All processing happens locally on your device using WebAssembly. Your files never leave your computer — close the tab and nothing remains.

Which browsers are supported?

Any modern browser on desktop or mobile: Chrome, Firefox, Safari, and Edge.

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