Blixt Wallet

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Frequently Asked Questions

Table of Contents

What is the Lightning Network?

Before you start using Blixt Wallet, it's important to get familiarized with terms, procedures, features, etc.

It's a good idea to start reading and get some basic knowledge about LN and how to use it, otherwise it will be difficult for you, as a new user, to understand what you are doing with Blixt Wallet as a node LN wallet.

Here are some resources to start learning:

A. General information and documentation about the Lightning Network

  1. An Overview of Lightning Network Implementations
  2. Lightning Network Resources, complete library about LN - by Jamesson Lopp
  3. LND Documentation - by Lightning Engineering
  4. Lightning Node Management – by openoms
  5. Lightning Node Management en Español – by openoms
  6. Beginners LN Guide 28 – by Bitcoin Q&A
  7. Lightning Network Dev Curriculum – by Chaincode Labs

B. Video tutorials about the Lightning Network and Bitcoin nodes

  1. What is a Bitcoin node
  2. The Lightning Network: The most efficient payment system in the world
  3. How LN channels work – by Decentralized Thought
  4. LN explained – by René Pickhardt
  5. LN Channels Management – by Alex Bosworth
  6. Everything you need to know about LN – Till Musshoff

Blixt doesn't sync. Why is this and what can I do?

First of all, let's explain some reasons for WHY it is not syncing, so the user can understand the situation:

  • The Blixt app needs to be online (connected to the internet) in order to connect to the Neutrino node and sync the block headers and filters. If your device, for some reason, is not connected to a stable internet connection, Blixt will stall the sync until it is restarted.
  • If you use the Tor network, the connection is quite unstable sometimes, not because of your device but because of poor or congested Tor relays in your area.
  • Keep in mind that Blixt uses quite a good amount of storage on your device, up to 1.5GB, so be sure to have enough free space, otherwise the app will stop the sync.
  • Sometimes the sync was not done properly and the app didn't scan all your BTC addresses.
  • If you switched to sync with your own home node, maybe your node was not prepared for this or connection with your node was interrupted.

So what you can do?

  • Restart the Blixt app (try force close for closing bad connections).
  • Remove Tor connection (if is possible and you want it) and restart Blixt.
  • Switch back to default sync server node.blixtwallet.com, or just leave it blank.
  • Go to Settings -> Rescan wallet, then restart the app. Once restarted, go to Settings -> Read lnd log, or go to Settings -> Copy lnd log to local storage to save a copy of the lnd log.
  • Check if you have enough space on your device. Move apps, photos, and videos to your mSD card, and leave more space on the local disk. Blixt needs up to 1.5GB for its data (block headers, LN graph, channels.db, etc).
  • Restart the app, then go to Settings -> LndMobile Help Center, and run a diagnostics test. Get in contact with Blixt support on Telegram for further instructions or to share logs.

What are the fees? Is there a cost to use LN channels?

1. Blixt Wallet itself does not charge any fees for usage of the app.

2. Use of the Lightning Network (LN) is not free! This is a myth. Even if the cost of using LN is really small, there is a cost, and some users will look at that cost too.

3. Opening and closing channels on LN has a cost, and sometimes it's not cheap. It also depends on the current miner fees when opening a LN channel. Sometimes it can be really high, sometimes it can be really low. Users should first learn about how fees work. To learn more about mempool, users can read What is Mempool?. To learn more about LN fees, users can read Lightning 101: Lightning Network Fees.

USE CASE SCENARIO:

You are a new Blixt Wallet user, and you have just installed the app. You have no funds deposited into the wallet.

Let's say you choose to use the Dunder LSP service (see down below how Dunder LSP works and what is LSP) to deposit 100k sats into your Blixt LN wallet.

The moment the LSP service receives your 100k deposit, it will use those 100k sats to open a 400k sats channel (amount can vary, see here for more details) towards your wallet. You will have 100k sats as outbound liquidity and 300k sats as inbound liquidity, but that opening comes at a cost: on-chain fees for the tx as well as a commit fee (reserve held for channel closure). More information on committing fees can be found in the following links:

With which nodes can I open lightning channels?

REMEMBER:

  • Blixt Wallet uses private channels, not routing channels.
  • You can open channels with whatever node peer you choose, but choose wisely.
  • Blixt Wallet is a private node wallet and mostly for quick payments. You will need to find the best routes: cheap, fast, reliable, and well connected peers.
  • You can connect to your own home node, but keep in mind that at that moment, your home node will be the liquidity provider for your wallet, so make sure it's reliable and you have good routes and good fees.
  • Not every LN node wants or agrees with private channels. If it is a dedicated routing node, they usually do not want private channels because for them it is like "locked" liquidity. It is better if you can first ask the node operator if they will agree to a private channel. You can open directly, but be aware that some of them can close the channel because they do not want private channels.

Blixt Wallet itself offers two optional methods for opening channels with the Blixt Node Server:

  • Autopilot: at the moment, it works only for the first on-chain deposit in Blixt and will open a channel with the Blixt Node for the amount you deposited.
  • Dunder LSP: Blixt Node Server will provide you with an inbound channel until 400k sats, on top of your deposit amount, to start with your first deposit on Lightning (if you do not have any other channel). You will need to activate it in the Settings menu.

Inbound liquidity providers - Blixt also offers a direct link, in the wallet, to LNBig and Bitrefill (Thor). Go to Settings -> Inbound channel services. Select the desired one, and follow the instructions provided. Those are used only when you need more "INBOUND" liquidity.

Open channels with any nodes - As we've pointed out, we recommend choosing your peers wisely. Blixt is a quick-spending LN wallet. We recommend finding one with low fees or even zero fees. Also, look at this Amboss Community of Zero Base Fee or any other node community. Your Blixt Wallet needs good peers and low fees, so your payments will be fast and cheap.

A very popular node that offers "zero fee routing" is the ZFR node. We suggest not opening small channels like 20k sats. If you want to use a node like this as a peer, at least open channels with 400-500-600k sats to have enough for your payments and also cover the reserves and costs. Smaller channels are not efficient for both peers. There are many others like this one, but also keep in mind the centrality and connectivity of those nodes. Not all will offer good routes for your payments.

It is very good practice to open channels with merchants or services you pay frequently. Opening a channel with your favorite merchant can bring you 0 fees since it is a direct channel and it is like a "line of credit." You can also use that channel to pay other merchants or services. Just be aware of their fees for routing your payment, because if there isn't a direct payment route, their node will have to route your payment to the next hop until it reaches the destination, and that comes at a cost.

How is it possible to have a node on a mobile device?

Blixt Wallet uses the lightning node implementation lnd and the Bitcoin SPV client Neutrino directly on the phone. Lnd has been configured to work well on mobile devices.

Keep in mind that Blixt Wallet is a Lightning node, with LN channels as any other node. That means that in order to be able to transact on LN, you need to be online and connected at the moment of the transaction. If you do not transact, it's not necessary to stay online. Blixt. Once Blixt is open, it will take a few moments to re-sync the latest blocks through SPV Neutrino, and you will be back online. On the other hand, for transacting on-chain (not LN), it's not necessary to be online.

Can I route payments with Blixt Wallet?

Blixt is not a routing node, it is more like a private LN node.

All channels on Blixt are private, which means they are not "visible" to the other routing nodes in the network. These so-called "unannounced" channels are used only for private payments.

Your Blixt LN node can send and receive payments using other nodes as hops, but can not route other payments through your Blixt node.

That's why Blixt is so special ... nobody knows about your payments. Check out this short tutorial about LN onion routing.

Can I receive sats through keysend?

Yes, always when your Blixt Wallet is online.

To display your nodeURI/QR code, go to Menu -> Advanced -> Keysend Experiment. Have the payer scan that QR code and pay.

Aspects to keep in mind:

  • If you want to share your nodeID on a website or send it to someone so they can pay you via keysend, your Blixt Wallet must be online at the time of the payment.
  • If you, as receiver, are using a Tor connection, the payer also has to use a Tor connection, otherwise they cannot "see" your Blixt node and connect with it.

How do I connect Blixt Wallet to my own full node?

Under Settings -> Bitcoin Node, you can enter a Bitcoin node to connect to.

Blixt Wallet does not yet support Tor Onion v3, so for the moment, you can only use your node if it is "visible" on clearnet (IP/domain). You must make sure that Bitcoin's P2P port (8333) is forwarded by your router. You can connect to your node via its local LAN IP, but it will only work if you're connected to your home router.

BIP157 compact filter indexing must be enabled for your node. Add this to your bitcoin.conf if it isn't already set:

      blockfilterindex=1
      peerblockfilters=1
    

Can I remotely control an Umbrel node from Blixt Wallet?

Blixt Wallet is a fully fledged lightning node in and of itself. It's not possible to connect to and control a remote node like Umbrel, myNode, RaspiBlitz, etc. For that management task, you would need to use apps like Zeus, Zap, Thunderhub, Ride The Lightning, or Fully Noded.

Instead of controlling your node from home, enable Tor and open a channel to it. That way, you could use your Blixt Node Wallet as a companion for your home routing node. See more details on the Guides page.

I lost my mobile phone (dead, stolen) or simply want to migrate to a new phone. What is the procedure?

RULE NO.1 - You should always have a channel backup and keep it in a safe place (e.g., password manager). If you did that, the procedure is simple and you have two ways (fast and slow) and also two situations to take into consideration (whether you had funds in on-chain or not).

RULE NO.2 - Never use a full backup of a device as a restored backup for BTC/LN wallets. This can result in losing funds by broadcasting the wrong state of channels.

NOTE NO.1 - Migration (or funds restore procedure) means creating a new Node ID and moving the restored funds to it. This is a better procedure for privacy, safety of funds, and overall ease of use.

NOTE NO.2 - If you have the ORIGINAL DEVICE still working and online with funds in LN channels, NEVER do the restore procedure on a new device with the channels restore options. This action will force close the existing channels and you could get a penalty for that (broadcasting twice the status of channels). You can ONLY restore the on-chain wallet/seed on another device, keeping the original still open, but never restore the channels backup.

NOTE NO.3 - If, after starting the restore process, you do not see in the "Lightning Channels" menu that the old channels have entered the status "closing," or if they are not there at all, it is safe to restart the restore process from the backup file. There is no need to start over from zero with an on-chain restore. If your on-chain wallet is restored and funds are back, it is OK to continue with LN channel restore.

NOTE NO.4 - If you restore LN channels that were open using the Tor network, then BEFORE starting the restore process, go to Settings -> Enable Tor. That way, your Blixt node can "see" the Tor peers and start the closing procedure in the normal way.

Scenario A - migrate Blixt to a new device (fast way)

Conditions:

  1. You still have the old device functional
  2. You have a new device ready with Blixt Wallet already installed (but not started yet)
  3. You have funds ONLY in LN channels, the on-chain is empty

Procedure:

  • Create a new Blixt wallet instance on the new device (new seed) and save that seed into a safe place (e.g., password manager).
  • Wait for Blixt to sync (takes just a few minutes), you will see the sync icon on the top right disappear.
  • On the new device Settings -> Enable Dunder LSP.
  • On the new device, go to main screen and click on the Receive button to create a new LN invoice to open a Dunder LSP channel.
  • Put the amount of total balance available displayed on the old device Blixt (main screen), then press CREATE INVOICE.
  • With the old Blixt device, scan the LN invoice QR code and pay it. The old wallet will send all available funds to the new one, and Dunder will open a new channel for you with that amount.
  • It will take a few minutes until the tx is confirmed and the channel is opened on the new device. Be patient.
  • Once you see the funds in the new device available, it is recommended to close those old empty channels. If there are some residual satoshis, they will go back to the on-chain wallet and can be sent later to the new device using an on-chain tx.
  • DONE! Blixt can now be deleted from the old device, and the funds are safe in the new one.

Scenario B - old device is lost, non-functional, or non-recoverable (slow way)

Conditions:

  1. You do not have the old device anymore
  2. You have a new device ready with Blixt Wallet already installed (but not started yet)
  3. You have funds in the LN channels but also in the on-chain wallet

Procedure:

  • Install Blixt Wallet on a new phone.
  • On the first screen to create or restore a wallet, go to Settings -> Enable Tor (if you previously opened channels with Tor nodes). You have funds in the LN channels but also in the on-chain wallet.
  • Blixt will restart in Tor mode. Then click on "restore." Fill in your 24 word seed from your old wallet, space delimited. You can also add the channels.backup file you saved previously and copy it onto your new phone. Optionally, you can use Google Drive, if you have it there.
  • Click "restore" and wait for the app to perform the standard procedure for recovering the funds.
  • Blixt will close the existing channels and, after a few blocks, funds will be recovered and visible in your on-chain wallet. Be patient.
  • To check the funds, go to Menu -> On-chain. Click the top right menu to see the Transaction Log. After channels are closed and txs are confirmed, locktime expires. The funds are displayed here.

I restored my old node using the SCB file, but funds are not back in my on-chain wallet.

OK, I had a previous dead node and I used the restore procedure, using the SCB backup channels file into Blixt. I wait for the channels to be closed, but funds are not back in my on-chain wallet. What can I do?

Usually, there are a few possible scenarios for closing channels:

  • A normal "cooperative close" channel usually takes a few blocks if both peers are online. Then everything goes smooth and fast.
  • If the other channel peer is not online, the closure task takes effect. This could take at least 144 blocks until funds are released from the lock time. Check the locktime for the closing tx on mempool.
  • A normal closure can be for many reasons, but mostly because of lost connectivity. If a normal closure gets stuck, then once the rest of the channels have entered into a "waiting to close" state, you could repeat the process to once again push the closure of the remaining stuck channels.
  • Another way to "push" the connection with your lost peers is to add them manually. Go to amboss.space, search for your peer, copy or scan the QR URI of your peer, and go to Settings -> Show Lightning Peers -> + .
  • To try a force closing action again, go to Menu -> Lightning Channels. Select the channel you want to push, and swipe on activity view to start the process again.

Once all the channels are initiated into "closing", wait patiently. This process takes time. If you see that on mempool the tx has released the funds, check your on-chain wallet. If funds are still not there, it means that the lnd wallet has to rescan previous addresses and refresh the wallet history. Some UTXOs are linked to "anchor outputs," so they are more complicated to get back on-chain.

When you see that all channels are closed, go to Settings -> Rescan wallet. Activate it and restart the app if it does not do so automatically.

Only when the lnd is initiated, can the rescan take place. Be patient and check the lnd logs (see Settings -> Read lnd log). You will read in there how it is scanning many blocks at once for your restored addresses. Once the process is finished, you should see the funds in the on-chain wallet.

Try to keep the Blixt app active during this process. If it is interrupted, you will have to restart again to trigger it.

IMPORTANT NOTES TO CONSIDER (in regards of how LN funds are moved):

  • When you open a channel of 2M sats with a peer, in the beginning, all the sats will be on YOUR side.
  • You start moving these sats by making payments and/or routing others' payments through this channel.
  • If you do not make your own payments out of your node, your balance will always be the same, but some channels will move sats in and out.
  • By routing others' payments, the dynamic of your channel's balances is changing. That is, if you started with 2M sats and routed 1M sats, your channel balance will be 1M sats. When you close that channel, you will get back 1M sats and NOT 2M sats that you had initially.
  • Before you begin to close your channels, remember the total balance you had in your node on YOUR side of the channels. That is the amount you will get back. Some channels will be empty on your side, so don't expect to get sats from those closed channels.