Lightning lets you send and receive bitcoin quickly, usually with low fees, without waiting for a separate Bitcoin blockchain transaction for every payment. In the mobile BitBoxApp, you use a separate Lightning wallet for these everyday payments while keeping your long-term savings in your on-chain Bitcoin wallet, where spending is protected by your BitBox.
The Lightning wallet is a hot wallet: its spending keys are stored on your phone, so you can pay without connecting your BitBox. Your BitBox helps create and recover this wallet, but it does not approve each Lightning payment.
Keep only a small spending balance
Anyone who gains access to the Lightning wallet's spending keys may be able to spend its balance. The feature is also in beta and may contain bugs, become unreliable, or stop working. Do not add more bitcoin than you are willing to lose, and keep large amounts and long-term savings in your on-chain BitBox wallet.
Ready to get started? Follow Set up a Lightning wallet in the BitBoxApp.
How funds move between Bitcoin and Lightning
For example, you can move a small amount from a BitBox Bitcoin account into your Lightning wallet, use your phone to pay for a coffee, and later withdraw unused funds to your on-chain account. Both balances are bitcoin; moving funds changes how you hold and spend them.
A top-up from your BitBox Bitcoin account is an on-chain transaction that you verify and confirm on the BitBox. It has a Bitcoin network fee and needs blockchain confirmations before the funds become spendable in Lightning. You can also receive a Lightning payment from another wallet without making an on-chain top-up first.
Once you have a Lightning balance, you can send and receive payments without connecting the BitBox. A withdrawal back to your Bitcoin account returns funds on-chain, so it also involves a fee and Bitcoin confirmation time.
What the BitBox protects
The two wallets appear in the same app, but their spending keys are protected differently:
| Security question | On-chain BitBox wallet | Lightning wallet |
|---|---|---|
| Where are the spending keys? | Inside your BitBox hardware wallet. | In the BitBoxApp on your phone. |
| Where do you approve a payment? | On the BitBox. | In the mobile app, without the BitBox. |
The BitBox derives a separate secret and asks you to approve creation of the Lightning wallet during setup. This does not give the app your original BitBox wallet seed. The derived Lightning secret cannot be used to calculate the seed or private keys of your on-chain wallet.
How Spark connects the wallet to Lightning
The BitBoxApp uses Spark, an off-chain system that connects to the Lightning Network. This lets you pay Lightning invoices and receive Lightning payments without running a Lightning node or opening and managing payment channels yourself. The app integrates these services through a software component called the Breez SDK.
The wallet is non-custodial because you control its spending keys through the BitBoxApp. However, transfers also depend on Spark operators cooperating and following the protocol. Holding the keys does not make the wallet independent of those services.
The current BitBoxApp does not support a unilateral exit, meaning you cannot independently force a withdrawal to the Bitcoin blockchain if the required Spark infrastructure is unavailable or uncooperative. This dependency also matters when recovering the wallet.
What your existing backup can restore
You do not need another set of recovery words for Lightning. The same BitBox wallet can recreate the Lightning wallet keys using a repeatable derivation based on BIP-85. If you lose the BitBox, restoring its existing backup on a replacement BitBox allows that device to derive the keys again.
Key recovery is only part of restoration: your BitBox backup does not contain all current Spark wallet data. The app still needs Spark to retrieve the balance, history, and wallet state. Recreating the keys alone does not guarantee access to the funds during a Spark outage. A wallet closed with Close and Withdraw Funds cannot be restored.
If the original BitBox wallet used an optional passphrase, you also need that exact passphrase. It is not included in the backup. The standard wallet and each passphrase-protected wallet derive different Lightning wallets. A passphrase determines which wallet you recover; it does not protect payments from a Lightning wallet already active on your phone.
Restore the BitBox backup only through the hardware wallet's recovery process. Never enter recovery words or backup contents into the BitBoxApp, a website, a chat, or a support form. For the derivation mechanism, see How the BitBox02 derives the Lightning wallet seed.
Restoring the wallet on another phone does not revoke access from a lost or stolen phone. If a phone containing the wallet is lost, stolen, or no longer trusted, treat its Lightning balance as at risk and contact BitBox Support for guidance. Never share wallet secrets with Support.
Fees and timing
Lightning payments and transfers to or from the Bitcoin blockchain have different costs and waiting times:
| Action | What to expect |
|---|---|
| Receive a Lightning payment | The recipient pays no fee in the supported receiving flow. The sender pays the Lightning payment fee. |
| Send a Lightning payment | The fee depends on the amount and available route. The app shows the fee and total balance deduction before you send. |
| Top up from a Bitcoin account | A Bitcoin network fee and blockchain confirmations apply. |
| Withdraw to a Bitcoin account | The app shows the applicable fee before confirmation. The resulting Bitcoin transaction needs blockchain confirmations. |
Lightning payments are generally quick and inexpensive, but a particular fee or completion time cannot be guaranteed. Funding your spending balance in advance avoids waiting for an on-chain top-up when you are ready to pay.
Availability
Lightning is available in the mobile BitBoxApp, not the desktop app. On Android, you can use an original BitBox02 or a BitBox02 Nova. On iPhone and iPad, you need a BitBox02 Nova. Bitcoin-only and Multi editions work the same way.
Use the latest supported BitBoxApp and the firmware offered through it. Check Supported devices and operating systems for the BitBoxApp for current platform requirements.
Choose your next step
Use the guide for what you want to do next: