ToolMintX
IT Tool

Clipboard Tester

Test browser clipboard copy, paste, read, write, permissions, secure context, and text clipboard support.

Instant 100% Client-Side No Login
PROCESSINGLOCAL
LIMITNONE
PRIVACYBROWSER-ONLY

Clipboard API Check

Write or read clipboard text to test browser behavior.

Secure Context

Needs HTTPS

Write Text

Unavailable

Read Text

Unavailable

ClipboardItem

Unavailable

Clipboard read result

Nothing read yet.

Write permission: unknown

Read permission: unknown

Reading the results

Clipboard access is one of the least consistent parts of the web platform, because it sits on a genuine security problem: the clipboard often holds a password, a 2FA code, or a wallet address the user copied moments ago from a different site. Browsers therefore allow writing fairly freely and guard reading heavily, and they disagree with each other about how.

That is why a copy button can work perfectly for you and fail for a user on a different browser. The four chips above separate the layers so you can tell which one is actually blocking you.

What each check means

Secure Context

Reads window.isSecureContext. HTTPS and localhost qualify; a plain HTTP page or a LAN IP like 192.168.x.x does not. If this chip is red, treat the other three as meaningless — the API is withheld before permissions are ever consulted. This is the single most common reason clipboard code works locally and dies on a staging box.

Write Text and Read Text

These probe whether navigator.clipboard.writeText and readText exist at all. Existence is not permission — a method can be present and still reject at call time. Write is broadly available; read is where browsers diverge, and it is normal to see Write supported and Read unavailable in the same browser.

ClipboardItem

Signals whether the browser can carry richer payloads than plain text — images, HTML, multiple MIME types in one clipboard entry. If you only ever copy strings you can ignore this chip. If you are building a "copy this chart as an image" button, it is the one that matters, since the plain-text methods cannot express image data.

Permission readouts

Check permissions queries the Permissions API for clipboard-write and clipboard-read. Expect unsupported on Firefox and Safari — they do not implement these permission names and have no plans to. That result does not mean copying is blocked; it means you cannot ask ahead of time, so the only reliable approach is to call the API and handle rejection.

Common failures and what they point to

NotAllowedError: Document is not focused

The clipboard call ran while devtools or another window had focus. The Clipboard API requires the document to be focused, which is why this error shows up constantly while debugging with devtools undocked.

readText is not a function

Firefox does not expose clipboard read to ordinary page scripts. The Read Text chip will show Unavailable there — this is by design, not a broken browser.

Write works, read silently fails

Writing is treated as low-risk and is allowed after a user gesture. Reading exposes whatever the user last copied — possibly a password — so it is gated far harder.

Everything unavailable on a staging URL

The page is on plain HTTP. Check the Secure Context chip first; every other chip depends on it.

Works standalone, breaks in an iframe

Embedded documents need clipboard-read or clipboard-write granted through Permissions-Policy on the iframe before the API is reachable.

Practical takeaway for your own code

Do not gate a copy button on a permission query. Because two major browsers report unsupported, a check-first approach disables your button for users whose clipboard would have worked fine. Call writeText inside the click handler, catch the rejection, and fall back to selecting the text so the user can copy manually.

For paste, prefer letting the user paste into a field over calling readText yourself. It works everywhere, needs no permission, and does not ask people to hand your page the contents of their clipboard sight unseen. Reserve programmatic read for cases where it genuinely earns the prompt.

One note on this page: clipboard text you read is rendered in this tab and nowhere else. It is not sent anywhere or stored. Even so, if what you last copied was a password or a recovery phrase, copy something harmless before testing read — good practice with any clipboard tool, including this one.

How to Use

1

Check clipboard support and permission state.

2

Edit the test text and copy it to your clipboard.

3

Read clipboard text back after granting browser permission.

4

Review secure context and Clipboard API support notes.

Features

Clipboard write and read testing
Clipboard permission state checks where supported
Secure context and ClipboardItem support detection
Useful for debugging copy/paste web app behavior

Common Questions

Use this clipboard tester to debug copy, paste, clipboard read, clipboard write, permission prompts, secure context restrictions, and Clipboard API support in Chrome, Edge, Firefox, Safari, and mobile browsers.

About Clipboard Tester

Check Clipboard API support for text copy, paste, read, write, permission states, secure context restrictions, and ClipboardItem availability. Useful for debugging copy and paste behavior in modern browsers and web apps.

Also known as: test clipboard, clipboard check.

Processing Note

Clipboard Tester runs in your browser, so the input you enter is processed locally on this page and is not uploaded to a ToolMintX account.

Tool Limits

IT tools provide quick diagnostics and transformations. They cannot see every private network, deployment setting, proxy, firewall, or production edge case.

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