Support FAQ

Fltr Wallet FAQ

Initially iOS and iPadOS are both targeted, meaning both modern iPhones and iPads are supported.

Support for macOS is planned and in the works.

Before a transaction goes into a block it stays in the mempool, which means it is seen by the network but not yet set in stone in the blockchain. This means the transaction can still be manipulated, the funds can be spent in another transaction and so on. Pending incoming funds cannot be spent until mined in a block.
Depending on the load of the network, in terms of transactions awaiting to be mined, the fee associated with the transaction tend to get more costly. Once the load decreases, even cheaper transactions are mined. Choose a higher transaction fee rate for the transaction to clear quicker.

Yes. You may have noticed that the QR code keeps changing as they are used. However, every code is monitored indefinitely and can therefore be saved or printed. This significantly lowers your privacy as users of the QR code are able to see the total funds sent to your address, if they want to.

It is advised to show the QR-pane in the App on either an iPad or iPhone as new addresses are generated automatically as they are used.

No, the way compact filters were designed it is suboptimal for wallet recovery. The key derivation in fltrWallet follows common standards so that it can be recovered by other software.
Currently, every device will get its own wallet. Synching of wallets between devices is on the roadmap.

The filter is a compressed representation of the information contained in a Bitcoin full block. The compression ratio is around 1:100 and achieves a negative predictive value of 1. Where as the positive predictive value is below 1. Hence, when the model matches the full block needs to be inspected.

In English please?

Instead of downloading every full block, which amounts to hundreds of megabytes daily, only blocks relevant to your transactions needs downloading. This saves downloading a lot of data.

Traditional wallets use Simplified Payment Verification and was originally outlined by Satoshi Nakamoto himself in the white paper. However, this is a centralized architecture where a mobile client connects to a single node. This also opens the door for fingerprinting of nodes and wallets, as well as attacks where nodes can withhold information from wallets. Bitcoin Core removed this feature as well as download of the mempool by default. Hence, the traditional mobile wallet should be considered a deprecated product.


Compact filters together with a multinode client stays closer to the original decentralized ideals in the Bitcoin design, more alike a full node. Block headers are synched first in a truly random process where each connected node is given equal opportunity to disclose its longest chain, making attacks much more difficult. Then compact filters can be downloaded as fast as possible and verified against the verified headers.

For Testnet, search for bitcoin testnet faucet and enter your address. The faucet will transfer a modest amount of Testnet bitcoins that you can control through the app.