Security built into how Kemback works

What it does

A personal finance app holds a detailed record of your life: what you earn, where you shop, who you pay. Kemback treats protecting it as part of the product, not an extra. That starts with what you can see and control, how you sign in and which devices are signed in, and continues with how the service stores and separates your data.

The full list is on the security page. Here is what it means in practice.

How it works in Kemback

Open Security in your settings. It has four parts.

• Passkeys. Sign in with your fingerprint, face or device PIN instead of a password. A passkey can’t be phished or reused on another site. Name each one, see when it was last used, and remove any you no longer have.
• Two-factor sign-in. Scan a QR code with an authenticator app and confirm it with a code. Kemback then gives you single-use recovery codes to keep somewhere safe. With two-factor sign-in on, a password alone doesn’t get anyone in, and a code can’t be used twice.
• Signed-in devices. Every browser and phone signed in to your account, with when it was last active. Sign out any of them with one click.
• Delete your account. If you ever want to leave, you can delete your account yourself, after downloading your data if you like.

Sign-in is also rate-limited, and repeated failures lock an account for a while, even against the right password. A wrong password and an unknown email fail in exactly the same way, so nobody can use the sign-in form to find out who has an account.

What happens behind the scenes

No bank passwords, ever

Kemback never asks for your bank password. Today, transactions come from files your bank gives you. When automatic bank sync arrives with the Plus plan, it will connect through Plaid, so your password goes to your bank, not to Kemback, and access is read-only.

Households kept apart, twice

Every request is scoped to your household in the application, and the database enforces the same rule again with row-level security. The service connects to the database with a role that can’t bypass it. So a mistake in one layer can’t show your data to someone in another household; a household that isn’t yours looks exactly like one that doesn’t exist.

Inside a shared household, any account can be private to one person. It never appears to anyone else, in the app or in their exports.

Secrets hashed or sealed

• Passwords are stored only as Argon2id hashes.
• Sign-in links, recovery codes and session tokens are stored only as one-way hashes.
• Anything Kemback must read back, like an authenticator secret, is encrypted with AES-256-GCM.

Encrypted in transit

kemback.com is HTTPS only. The iPhone app also pins the certificate authorities kemback.com’s certificates come from, so it won’t talk to a server pretending to be Kemback.

A tamper-evident record

Every change in a household is written to an activity log where each entry is chained to the last, so the history can be checked and can’t be quietly rewritten. In a shared household, that answers “who changed this?”.

Quiet on the lock screen

Alert emails and iPhone notifications say only how many alerts there are in the subject line or on the lock screen, never amounts or account numbers.

Where it runs

Passkeys, two-factor sign-in and the device list are in any browser at kemback.com and in the iPhone app, which is in beta. The iPhone app can also lock itself with Face ID, Touch ID or your passcode when you leave it. Every security feature is on the Free plan; none of it costs extra.

Kemback runs on servers rented from Hetzner in Germany, and the security page lists where your data lives. For practical steps that protect every financial account you have, read protecting your money online with passkeys and 2FA.

Questions

Does Kemback store my bank password?

No. Kemback never asks for it. Today you import files your bank gives you. Automatic bank sync, coming with the Plus plan, will connect through Plaid, so your password goes to your bank, not to Kemback, and access is read-only.

Can I sign in with a passkey?

Yes. Add a passkey from the Security page and sign in with your face, fingerprint, device PIN or a security key instead of a password.

Does Kemback support two-factor authentication?

Yes. Turn on two-factor sign-in with an authenticator app. You get single-use recovery codes when you set it up, and with it on, a password alone doesn't sign you in.

Can other households ever see my data?

Every request is limited to your household by the application, and the database enforces the same limit again with row-level security, so a mistake in one layer can't show your data to anyone else.

Does Kemback sell my data?

No. Kemback is paid for by its plans. It doesn't sell or rent your data, or use it to show you financial product offers.

What does a lock-screen notification show?

Only how many alerts there are. Alert emails and iPhone notifications never put amounts or account numbers in the subject line or on the lock screen.