Zero-knowledge · end-to-end encrypted
Your clipboard, everywhere.
Readable only by your devices.
Copy on one device, paste on another — text, images, and files sync
instantly and privately. Everything is encrypted on your device with
X25519 & AES-256-GCM; the relay only ever sees ciphertext.
No account. No tracking. Nothing is stored on the server until you
create a channel.
🔒
Zero-knowledge
Keys never leave your device. The server can’t read a single byte
— not even file names.
⚡
Instant sync
Real-time over WebSocket with polling fallback, using
last-write-wins so the newest copy always wins.
📱
Every device
Pair by link or QR, verify with a safety number, and manage
multiple channels — phone, laptop, desktop.
🧹
Self-cleaning
Channels auto-expire when idle; the creator can revoke a device or
tear a channel down instantly.
- 1 Create a channel on this device.
-
2 Share the link + code (or scan the QR) on another.
- 3 Copy here, paste there — end to end encrypted.
🕵️
Private by design
We don’t want your data — so the system is built never to receive
it in a readable form.
- No accounts, no email, no sign-in — ever.
- No analytics, trackers, cookies, or ads.
- Nothing touches the server until you create a channel.
-
The relay only sees ciphertext — never your text, images, or
file names.
- Idle channels auto-expire; wipe one instantly, any time.
🛡️
Secure by cryptography
Modern, fixed, end-to-end encryption — nothing to misconfigure.
- X25519 key agreement · AES-256-GCM · HKDF-SHA256.
- Keys are generated on-device and are non-exportable.
-
Pairing verified by a 6-digit code + safety number
(MITM-resistant).
-
Group keys rotate on every join & leave (forward secrecy).
- Revoke a device and it is cryptographically locked out.
Channel
connecting…
manager
1 device
Latest incoming
nothing yet
Activity log
Privacy Policy
Last updated: 2026
ZeroClipboard is a zero-knowledge service, engineered so that neither
we nor the relay server can read anything you sync. We don’t want your
data, so the system is built never to receive it in a readable form.
What we do not collect
- No accounts, names, emails, or passwords.
-
No analytics, tracking pixels, cookies, fingerprinting, or ads.
-
No clipboard content, files, or file names — these are end-to-end
encrypted and never leave your devices in plaintext.
What the relay handles
To route messages between your devices, the relay transiently holds
only ciphertext plus minimal routing metadata: a random
channel id, device ids, timestamps, message type, and byte size. It
never holds your keys and cannot decrypt anything.
Retention
Channels are ephemeral. A channel that never pairs a second device
expires within about a day; an inactive channel expires within about a
month; and the creator can expire a channel manually at any time.
On your device
Your encryption identity and channel list live locally in your browser
(IndexedDB) and are never uploaded. Clearing browser storage removes
them.
Contact
Questions? Reach the author at
deb0.com.
Security
Security is the product. ZeroClipboard uses fixed, modern primitives
with no downgrade options.
Cryptography
- Key agreement: X25519 (ECDH).
- Encryption: AES-256-GCM (authenticated).
-
Key derivation: HKDF-SHA256 ·
Hashing: SHA-256.
- Private keys are generated on-device and are non-exportable.
Pairing & verification
Pairing uses a 128-bit secret split between an invite link and a
separate 6-digit code. Devices verify each other end-to-end with an
HMAC key binding, and a human-checkable safety number defends against
a man-in-the-middle.
Forward secrecy & revocation
Group keys rotate on every membership change, so a new device can’t
read past messages and a departed device can’t read future ones.
Revoked devices are tombstoned and locked out; a revoked device wipes
its own keys.
Threat model
The relay is treated as untrusted: it can observe traffic timing and
ciphertext sizes and can deny service, but it cannot read your
content.
Responsible disclosure
Found an issue? Please report it privately to the author at
deb0.com.
Terms of Service
Last updated: 2026
By using ZeroClipboard you agree to these terms.
Service “as is”
ZeroClipboard is provided free of charge, “as is”, without warranties
of any kind. The relay is best-effort with no uptime guarantee, and
channels may expire as described in the Privacy Policy.
Acceptable use
You are responsible for what you sync. Don’t use the service for
unlawful purposes or to infringe others’ rights. Because content is
end-to-end encrypted, you alone control and are accountable for it.
No liability
To the maximum extent permitted by law, the author is not liable for
any damages arising from use of the service.
Author
Built by
Debajyoti Saikia.
