FAQ and security

No. Your wallet keys are generated or imported on your device. We do not hold a copy enabling us to dispose of your BTC and do not maintain a withdrawable customer balance.

Actual key and control rights determine this. KAI-Pay uses Spark via the Breez SDK. Spark requires the Spark operators to cooperate for payments. Spark also provides a unilateral exit that works without the Spark operators; what it requires is explained under “What if the service closes?”.

Not automatically. Each additional service requires separate assessment.

No. We do not have a copy of your 12 words and never ask for them. Never share them with anyone – neither with us nor with third parties.

To restore your wallet in KAI-Pay: yes, provided the Spark operators cooperate. KAI-Pay derives the wallet from the 12 words alone and does not use Lightning channels of its own for you whose data would need a separate backup. A passkey wallet also shows you the 12 words; they work without the passkey.

You set up your PIN and fingerprint unlock again on the new device. The 12 words alone are not enough for a unilateral exit without the Spark operators (see “What if the service closes?”). Test recovery before you transfer funds to the wallet.

Usually not technically after settlement; we cannot reverse completed payments either. Legal claims against recipients or providers may remain.

Check the existing transaction first to avoid duplication. If the outcome of a payment is unclear, the app shows “Outcome not yet clear – being checked”. The activity list shows the payment's status: “Completed”, “Pending” or “Failed”. If an earlier payment is still pending, the app points this out before you send again.

KAI-Pay currently charges nothing for the wallet itself. Payments may incur third-party fees, for example for the Bitcoin network, Lightning routing or Spark.

When you send, the app shows the amount, fee and total before you confirm. If receiving via a Lightning invoice incurs a fee, the app shows it together with the invoice. When receiving to a Bitcoin address, a fee may apply for crediting the funds; the app does not show it in advance. A displayed EUR or USD equivalent is an approximation and does not guarantee future BTC value.

It depends on whether you have backed up your 12 words. The app keeps your wallet data in your browser's storage on this device; your 12 words are stored there only in encrypted form. If this data is deleted – for example in the browser settings or with “Remove wallet from this device” – the wallet can only be restored with your 12 words, or with the passkey for a passkey wallet. Deleting an app is not a backup.

Restore the wallet on a clean device with your 12 words (“Restore wallet”). If your keys may be exposed, safely move the remaining funds to a new wallet with new 12 words.

This also applies if the wallet on the lost device was protected by a PIN: the words are encrypted there, but anyone with access to the device data can try every possible 6-digit PIN. Never send your 12 words to us or to third parties.

Your keys are not held by us. KAI-Pay derives your wallet from your 12 words alone, using the open-source Breez SDK Spark; KAI-Pay servers are not involved in this. With the 12 words, the wallet can therefore in principle also be restored with other software based on this SDK, as long as the Spark operators cooperate. A passkey, by contrast, is tied to app.kai-pay.net. If that site is no longer available, only your 12 words will help, even for a passkey wallet.

Spark also provides a unilateral exit: funds can be moved back to the Bitcoin blockchain without the Spark operators' cooperation. This requires exit data stored on the device – the 12 words alone are not enough – and your own on-chain bitcoin to pay the network fees. Because of time locks in the Bitcoin network, the exit can take several days. It does not succeed in every case; for small balances, the fees can exceed the balance itself. The KAI-Pay app does not currently offer it as a feature of its own.

Dependencies on the Bitcoin network and on providers such as the Spark operators may remain.

KAI-Pay cannot replace missing keys. Arrange secure succession or representation outside unprotected communication channels.

No, there is no anonymity guarantee. Network and transaction data may be linked. The privacy policy explains which data goes to whom.

No. Exporting your activity as a CSV file and statutory reporting by providers do not discharge your own duties. The CSV export currently covers at most 100 payments and therefore not necessarily your full history.