ClientSideTools Privacy-First Browser Tools

Clipboard API & Paste-Event Auditor

Silent clipboard reading and "paste-jacking" (where copied content carries hidden HTML, scripts, or zero-width characters) are real security risks. This auditor shows your clipboard permission state, lets you test read/write, and inspects every paste event for hidden or malicious content.

Privacy, Security & Web APIs 100% Local Clipboard data stays in your browser. Never transmitted.

Tool interface

🔐 Permission State

Current clipboard permission status reported by the Permissions API.

📋 Read / Write Test

🕵️ Paste-Event Auditor

Click the zone below, then press Ctrl+V (or Cmd+V) to paste. The event is intercepted and analyzed for hidden content — nothing is actually inserted.

Click here, then paste (Ctrl+V / Cmd+V)

Introduction

The clipboard is a surprisingly rich attack surface. Beyond simple text, copied data can carry HTML with embedded scripts, hidden styles, or invisible Unicode. This tool gives you visibility into your clipboard permissions and lets you inspect exactly what a paste event contains.

How It Works

  • Queries navigator.permissions for clipboard read/write state.
  • Tests navigator.clipboard.readText(), read(), and writeText().
  • Intercepts paste events and enumerates every DataTransfer MIME type.
  • Runs a paste-jacking detector that flags event handlers, hidden elements, zero-width characters, and HTML/text mismatches.

Privacy

All clipboard operations run locally in your browser. Clipboard content is never transmitted. No API calls, no tracking.

Limitations

  • Clipboard reading requires a secure context and may require explicit permission depending on the browser.
  • Firefox does not support clipboard-read via the Permissions API or clipboard.read().
  • The paste interceptor calls preventDefault(), so content is analyzed but not inserted.

FAQ

Why does "Read Clipboard" fail?

Clipboard reading requires a user gesture and granted permission. If the browser blocks it, you'll see a permission error. Some browsers also restrict reading to text only.

Is my clipboard content uploaded?

No. Everything stays in your browser and is never transmitted.

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Version and changelog

  • Version: 1.0.0
  • Last updated: August 13, 2026
  • Changelog: Initial production release.