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There are two ways to back up a Bark-based wallet.
  1. Record the mnemonic (seed phrase): This alone is enough to recover a wallet’s balance, with the Ark server’s cooperation. It can’t restore payment history or the state of any in-progress exits, and it’s also the key that decrypts encrypted continuous backups.
  2. Maintain a continuous backup of the wallet database: A backup the user fully controls. It restores a wallet in full, payment history and in-progress exits included, without any support from the server.

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Seed phrase backups

Every Bark wallet posts a record of its VTXOs to a mailbox on the Ark server that only its mnemonic can unlock. A wallet restored from the mnemonic alone derives its keys, pulls the VTXO record back, verifies every VTXO, then rebuilds the spendable off-chain balance. A chain scan then recovers the on-chain balance. The seed phrase alone is a safety net, but it isn’t a complete backup.
  • The backup depends on the server to cooperate and respond with the required data.
  • It restores the balance, not the payment history or the state of an in-progress exit.

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Revealing the seed phrase

The SDK does not hold the mnemonic for you by default. You’ll need to ensure your app generates it, stores it, and reveals it when required.
1

Generate the phrase

Call generateMnemonic and pass the result in when you create the wallet.
2

Store it securely

Write the phrase to your app’s secure storage.
3

Offer a reveal screen

Show the words on demand from a settings screen, behind your app’s own authentication.

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Continuous backups

To ensure users don’t have to rely on the Ark server for backups, your app should keep backups of the wallet database that update after every wallet state change, in addition to recording the mnemonic. An up-to-date wallet database backup includes all the off-chain transactions that make up a user’s VTXOs. Therefore it will restore the wallet in full: the whole balance, the payment history, and any in-progress exits, all without the Ark server’s involvement. Any good backup solution follows three rules.
  • Back up on every state change, not on a schedule: Wallet state changes with every board, send, receive, refresh, offboard, and exit. Anything a backup misses can only be recovered through the seed phrase mailbox.
  • Store backups somewhere that outlives the host device: A copy kept on the wallet’s own device disappears with it.
  • Encrypt backups with a key derived from the mnemonic: The seed holder can always decrypt, so a restore needs nothing but the phrase, and the backup grants no access that the seed doesn’t already grant.
How you make continuous backups depends on what you’re building on.
The SDK persists wallet data through the storage your app provides, so backing it up is your app’s responsibility.

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Mobile and desktop apps

Wallet data typically lives in the app sandbox. Backups should go to storage that the user controls, such as their platform-native cloud drive, after each state change.Noah, a full-stack React Native wallet, has a mature example of mobile backups for Bark.

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Web apps

In the browser, the SDK stores wallet data in IndexedDB. IndexedDB is scoped to the site origin and can be evicted by the browser, so it’s even more important to ship every change to another secure location and to make sure the user has recorded their mnemonic.