Clipboard history is safe for passwords only if the manager filters them. A clipboard manager records what you copy, so a password or an API key copied in clear can sit in its history file, in plain text, for weeks. A good one skips copies that password managers mark as concealed, ignores the password managers themselves, recognises keys and tokens by their shape, and keeps its history on your Mac. Pasteback, Toolnotch's clipboard history, does all four, and shows the secrets it keeps masked on screen.
Here is what macOS does on its own, what to check in any clipboard manager, and exactly what Pasteback does.
What macOS does with a copied password
The Mac's clipboard holds one item. Copy a password and it stays there until you copy something else, readable by any app that asks for the clipboard. macOS doesn't clear it after a delay.
Two things help:
- Password managers mark their copies. 1Password, Bitwarden, KeePassXC and others add an invisible marker,
org.nspasteboard.ConcealedType, when they put a password on the clipboard. It's a convention from nspasteboard.org that tells clipboard managers "don't record this". Many also clear the clipboard after a minute or so. - Universal Clipboard sends what you copy to your other Apple devices nearby. It's handy, and it also means a password copied on your iPhone can arrive on your Mac. Turn it off in System Settings › General › AirDrop & Handoff ("Allow Handoff between this Mac and your iCloud devices") if you'd rather it didn't.
Recent macOS versions also offer a clipboard history in Spotlight. It's off by default; if you turn it on, check how it treats passwords before relying on it.
What to check in any clipboard manager
- It honours the concealed marker. This is the minimum. Copy a password from your password manager and check the history: it shouldn't be there.
- It can ignore apps. Some password managers or browser extensions forget the marker. A list of apps whose copies are never recorded catches them.
- It recognises secrets you copy yourself. An API key copied from a web dashboard or a
.envfile carries no marker. Only pattern matching on the content catches it. - History stays local. Sync is convenient; it also means your clipboard, secrets that slipped through included, lives on a server.
- It masks what it keeps. A history open on a shared screen or during a call shouldn't show a token in full.
What Pasteback does
Copies from password managers are never recorded
Pasteback skips any copy that carries the concealed, transient or auto-generated marker. On top of that, "Filter password managers" (on by default) skips copies made in 1Password, Bitwarden, LastPass, Dashlane, KeePassXC, Enpass, NordPass, RoboForm, Keeper, Proton Pass, Apple's Passwords app and Keychain Access, even when the marker is missing. Nothing of those copies is written to disk. The notch tells you so with a short island, « Not saved · password manager », at most once in a while so it doesn't nag.
You can add any other app to the ignored list in Settings › Pasteback › Privacy & secrets, or switch to allowlist mode, where only the apps you list are recorded.
Keys and tokens are recognised by their shape
For what you copy yourself, Pasteback checks the text against the formats credentials use: OpenAI and Anthropic keys, Stripe keys, GitHub, GitLab, Slack, npm, Hugging Face and Linear tokens, AWS access key IDs, Google API keys, JSON Web Tokens, Bearer headers, PEM private keys, connection strings with a password (postgres://user:password@host), .env lines such as DB_PASSWORD=… or API_KEY=…, JSON fields like "client_secret": "…", and password: … lines. Each rule targets a distinctive prefix or structure, to avoid masking ordinary code.
What happens next depends on the Secrets setting:
| Mode | What it does |
|---|---|
| Temporary (default) | The secret is kept, masked, in memory and in your Mac's Keychain, never in the history file. It's deleted when the Mac restarts, or after 10 minutes, 1 hour, 8 hours or 24 hours if you choose. |
| Block | The secret is never recorded. The island says « Secret copied · not saved ». |
| Keep | Recorded like any other clip, still masked on screen. |
When a secret is kept, the island under the notch reads « Secret copied · clears at restart » in amber.
Masked on screen, real on paste
In the history (⇧⌘C), a secret shows a lock, a name taken from its prefix, and its first characters followed by dots: API key sk-de••••••••, Stripe test key sk_test_••••••••, GitHub token ghp_Ab••••••••. At most eight characters ever show, never the end, and the dots are always the same length, so they don't reveal how long the value is. For an .env line, the variable name stays readable: POSTGRES_PASSWORD=••••••••.
The preview says it plainly: « Masked here and never written to disk. Paste still sends the real value. » Press ↩ and the full key goes into the app you came from. To check a value, click Show or hold ⌥.
When Pasteback pastes a secret, it puts it on the clipboard the way password managers do: with the concealed marker, so other clipboard managers skip it, and for this Mac only, so Universal Clipboard doesn't hand it to your iPhone.
A Secrets filter in the history lists them all, which makes it quick to find a key you copied an hour ago without seeing it in clear.
Passwords you type yourself
A plain password such as Tr0ub4dor&3 has no prefix to recognise. Pasteback masks text that reads like one (8 to 64 characters, no spaces, at least three of lowercase, uppercase, digits and symbols, and not an address, a path, a version number or another everyday shape) to its first two characters: Tr••••••••. This check is deliberately softer than the storage rules, so it can mask a harmless string now and then, and it changes the display only: the clip is kept as copied, and the preview says « Masked on screen only; kept as copied ». If that matters to you, copy passwords from a password manager, which Pasteback never records.
Links that carry a token
A magic link or a reset link (…/verify?token=…) stays readable as a link, with only the credential values masked (?token=••••). Pasteback doesn't fetch a preview for it either: some of those links work once, and opening one in the background would burn it.
Local only
The history, secrets included, stays on your Mac. There's no account, no cloud and no sync.
Limits worth knowing
- Pattern matching has gaps. A key from a service whose format isn't in the list, with no telling prefix, can be stored in clear (the password heuristic may still mask it on screen). The Block mode and the ignored apps list are there for stricter needs.
- Universal Clipboard copies. A copy arriving from another device has no app to filter on, so only its content decides. A password copied on your iPhone is masked on screen at best, unless the concealed marker survives the trip. Turn Handoff off if that worries you.
- Temporary means temporary. By default, a secret disappears from the history when the Mac restarts. That's the point; pin what you need somewhere safer, like a password manager.
FAQ
Do clipboard managers save passwords?
Some do. A clipboard manager records what you copy unless it filters it. Check that yours ignores copies marked as concealed by password managers, and test it: copy a password and look at the history.
Is Pasteback safe to use with 1Password or Bitwarden?
Yes. Their copies carry the concealed marker, and both apps are on Pasteback's list of password managers, so their copies are never recorded. Apple's Passwords app and Keychain Access are on it too.
Can I see a masked secret?
Yes. Select it in the history and click Show, or hold ⌥. It masks again when you move to another clip.
Does Toolnotch send my clipboard anywhere?
No. The history, including image text recognition, stays on your Mac. More on the clipboard history itself in clipboard history on Mac, and on the licence in pricing.