Clipboard Tester

How to use the clipboard tester

1. Copy the sample text, then paste it somewhere to confirm.
2. Try reading the clipboard back.
3. Read the explanation if either step fails.

About this tool

Copying and reading are governed by different rules, and knowing which is which explains most clipboard problems.

Writing is permitted when it follows a click, because clicking a copy button is clear intent. Reading is far more sensitive: the clipboard may hold a password or a card number you copied minutes ago, so browsers require explicit permission — and Firefox and Safari refuse it to pages entirely.

So a page that cannot read your clipboard is almost always working correctly. If writing fails too, the usual causes are an insecure http connection, which disables the API, or the browser blocking clipboard access for the site.

Common uses

• Working out why a copy button does nothing on a site.
• Checking clipboard support in a locked-down or managed browser.
• Confirming an extension is not interfering with copying.

Frequently asked questions

Why can this page not read my clipboard?

Reading exposes whatever you last copied, which might be a password. Browsers require permission for it, and Firefox and Safari refuse it to pages altogether.

Why does copying fail?

Usually an insecure http connection, which disables the clipboard API, or the browser blocking clipboard access for the site.

Can this page see what I have copied?

Only if you press Read clipboard and your browser allows it, and even then it stays on your device. Nothing is transmitted.