On-Device vs Cloud Password Managers: Where Your Extension Sends Your Data
Two extensions can look identical in the browser and be built on completely different trust. One keeps a copy of your vault on a company's servers; the other never lets it leave your device. The difference shows up on the worst day.
Every password-manager extension puts a friendly little icon in your toolbar. Behind that icon, though, sit two very different architectures, and the choice between them decides who could be affected when something goes wrong.
The common model is cloud-first: your encrypted vault is stored on the vendor's servers and synced to each device, where the browser extension decrypts it locally. The alternative is on-device: the vault lives only on your machines, and the extension is just a way to reach the copy that is already there. Kinship Vault is built the second way. Here is what that actually changes.
Key takeaways
- Cloud managers store your encrypted vault on their servers; on-device managers do not.
- Both encrypt your data, but only one creates a central copy that a breach could expose.
- An on-device extension decrypts nothing in the browser; it asks the local app to do it.
- You can tell which you have by asking one question: if the company vanished, could you still open your vault?
The part that looks the same
Reputable managers of both kinds use strong encryption and never hold your master password. That is real, and it is why "the vendor was breached" does not automatically mean "my passwords are readable." But encryption is only half the story. The other half is where the encrypted copy lives and where it gets decrypted, and that is where the two models split.
The part that differs
| Cloud-first | On-device (Kinship Vault) | |
|---|---|---|
| Where the vault is stored | Vendor servers, synced to you | Only on your devices |
| Where it is decrypted | In the browser extension | In the app, behind Face ID / Touch ID |
| What a server breach exposes | Encrypted vaults, metadata, URLs | Nothing; there is no server copy |
| What the extension sends out | Sync traffic to the vendor | Only the page hostname, to the local app |
| If the company disappears | Sync stops; export needed | Your vault still opens, offline |
The cloud model's convenience is real: your vault appears on every device with an account login. But it also means a single, valuable target, your encrypted vault plus the metadata around it, exists on infrastructure you do not control. History has shown that even well-run companies get breached, and that leaked encrypted vaults become offline cracking projects against whoever used a weak master password.
Encryption decides whether a stolen vault can be read. Architecture decides whether there is a stolen vault at all.
Why "decrypted in the browser" is worth noticing
In a cloud-first extension, the vault is decrypted inside the browser process so it can fill forms. That puts your unlocked secrets in the most exposed, most extended part of your computer, right next to every other extension you have installed. An on-device design avoids this: the browser extension never holds the vault or the key. It asks the Kinship Vault app to decrypt a single login, and only after a biometric check. The browser sees the one password it needs, at the moment you asked for it, and nothing more.
What you give up, honestly
On-device is not free of trade-offs. Syncing across your devices happens through channels you control rather than a vendor account, and there is no server-side copy to fall back on, which is exactly why a recovery plan matters more here, not less. The upside is that the thing protecting you is math and hardware on your own device, not a promise about someone else's servers.
How to tell which you are using
You do not need to read a whitepaper. Ask one question: if this company shut down tomorrow, could you still unlock your vault on your own device, offline? If yes, your data is on-device. If you would lose access or need to scramble for an export, it is living in someone else's cloud. With Kinship Vault the answer is yes, because the vault was never anywhere else. The browser extension is just the door to it.
An extension that reaches your vault, not a copy of it.
Kinship Vault fills your logins on the web while the vault stays encrypted on your device, with no server holding a copy.
Explore the password manager