Clipboard Manager & Tester

About Clipboard Manager & Tester

The Clipboard Manager & Tester is a developer tool for testing and debugging the modern Async Clipboard API. It provides real-time feedback on clipboard operations and permission states, making it essential for developers implementing copy/paste functionality in web applications.

Core Features

1. Permission Monitoring: Real-time tracking of clipboard-read and clipboard-write permission states (Granted, Prompt, or Denied). Instantly see how your browser handles clipboard access.

2. Write Operations (Copy): Test navigator.clipboard.writeText() with custom text input. Verify that your clipboard write operations work correctly across different browsers and security contexts.

3. Read Operations (Paste): Test navigator.clipboard.readText() to retrieve current clipboard content. Understand how permission prompts work and troubleshoot read access issues.

4. Error Diagnostics: Detailed error messages help identify common issues like permission denials, security context problems, or API unavailability.

Technical Requirements

Secure Context Required

The Clipboard API is only available in secure contexts:

• HTTPS websites (recommended for production)
• localhost (for local development)
• 127.0.0.1 (for local development)

HTTP sites will not have access to the Clipboard API for security reasons.

Permission Model

Clipboard access follows a strict permission model:

• Write Access: Generally granted automatically when triggered by user interaction (button clicks, keyboard shortcuts). No permission prompt typically required.
• Read Access: Highly restricted due to privacy concerns. Browsers will show a permission prompt that users must explicitly accept. This prevents malicious sites from silently reading sensitive clipboard data.

Browser Compatibility

Modern browsers support the Async Clipboard API with varying levels of implementation:

• Chrome/Edge 66+: Full support for text operations
• Firefox 63+: Full support with permission prompts
• Safari 13.1+: Supported with security restrictions
• Mobile browsers: Support varies; may require specific user gestures

Note: Older browsers may not support the Async Clipboard API. Check navigator.clipboard availability before using.

Common Use Cases

This tool helps you:

• Debug clipboard functionality during development
• Test permission handling across different browsers
• Verify security context requirements
• Reproduce clipboard-related bugs reported by users
• Understand browser-specific behavior differences
• Test user interaction requirements for clipboard access

Troubleshooting Guide

"Clipboard API not supported"

Causes:

• Browser doesn't support the Async Clipboard API
• Page is accessed via HTTP instead of HTTPS
• JavaScript is disabled

Solutions:

• Use a modern browser (Chrome 66+, Firefox 63+, Safari 13.1+)
• Access the page via HTTPS or localhost
• Enable JavaScript in browser settings

"Read failed - Permission denied"

Causes:

• User denied clipboard read permission
• Permission was previously blocked for this site
• Browser security settings prevent clipboard access

Solutions:

• Click the permission prompt to allow access
• Reset site permissions: Browser Settings → Privacy & Security → Site Settings → Clipboard
• Check for browser extensions blocking clipboard access
• Try in an incognito/private window to test with fresh permissions

"Write failed"

Causes:

• No user interaction before write attempt
• Browser blocked the operation due to security policy
• Clipboard is locked by another application

Solutions:

• Ensure write is triggered by user action (button click)
• Check browser console for specific error messages
• Close other applications that might lock the clipboard

Privacy & Security Considerations

The Clipboard API is designed with privacy in mind:

• User consent required for reading clipboard data
• No silent clipboard access - users must approve read operations
• Secure context only - prevents HTTP sites from accessing clipboard
• Transient permissions - some browsers reset permissions after tab close

Always inform users when your application needs clipboard access and explain why it's necessary.

Developer Tips

• Always check API availability: Use if (navigator.clipboard) before accessing the API
• Handle permission denials gracefully: Provide clear feedback when permissions are denied
• Test across browsers: Clipboard behavior can vary significantly between browsers
• Use user gestures: Trigger clipboard operations from button clicks or keyboard events
• Provide fallbacks: Consider implementing a fallback for browsers without Clipboard API support

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