I recently had the honour of being an MC alongside Desiree Dickerson of the inaugural Lightning Conference in Berlin, October 2019. This was an incredible event gathering together all the stars of Bitcoin’s Lightning Network, facilitating unmissable education, discussion and collaboration. The pre events included a Lightning Network Socratic Seminar, Lightning Network projects discussion, and a “Meet the Devs” event. The conference itself involved talks across two stages, with a separate area for workshops/hacking space. I wanted to capture some of the themes of discussion, as well as some of my own reflections, so here goes:

Further recognition about things that will change

Rusty Russell mentioned the necessity of not making mistakes made in Bitcoin’s past, where some businesses assumed that bitcoin fees would remain cheap indefinitely. So consequently we should recognise that lightning routing fees will rise over time.

Alex Bosworth’s talk about Lightning and liquidity, made it clear that currently, most Lightning routing node operators are not professionally managing channels. We should anticipate this will change in future and more care will be taken to commit bitcoin into channels that make sense for the node operator, and for that node operator to monitor the health and balances of their channels.

Max Hillebrand pointed out some privacy improvements required with Lightning nodes, some of which will announce their private channels as part of a ‘route hint’. Though it’s fair to say there could be some tension between making it more private, while still achieving high routing success probability.

Lightning network powered gaming

I noticed some interesting efforts to make lightning network powered gaming a reality with efforts by Satoshi Games, Donnerlabs and Zebedee. These may end up helping ‘grow the pie’ of people interested in Bitcoin and Lightning if there are gamers who get into earning bitcoin through games. Though it’s also clear that these games have to be good enough in their own right to draw gamers in, otherwise it only appeals to the existing Lightning user base which is simply not big enough. The multi prong approach by Zebedee of creating games, but also creating toolkits and helping other game developers put bitcoin/lightning into their games struck me as a clever one. I don’t really play games nowadays but thinking back to when I was a teenage boy, I can definitely see the appeal in playing games to stack sats!

Mobile lightning wallets vs remote controlled home nodes

There were plenty of opportunities to spend using the lightning network over the week, ranging across robo-cocktail and beer machines, to coffee carts and ice cream. Merchants were using some combo of BTCPayServer, custom payment devices, to simply using Wallet of Satoshi.

Beer paid for with Lightning Network!

Photo credit: Enid Valu @WarmDefeat (see gallery here)

Personally, my approach was to use Zeus wallet for Android, connecting over Tor to remote control my Raspberry Pi 4 LND node running at home on the other side of the world. Generally I found this to work quite well, with no routing failures. Some of the difficulties I faced were more around having poor mobile internet connectivity causing slower lightning invoice lookups, or some bugs in the lightning apps. However in fairness, these are early stage apps and they’re rapidly being improved to cut out unnecessary steps and remove bugs. Other popular wallets that can remote control a home full node include Zap and Spark.

Turning to mobile nodes/wallets, I saw many use Eclair, Breez, Blue Wallet, and Wallet of Satoshi. There are trade offs inherent to these mobile node wallets and I prefer using the ‘remote control your home node’ setup. But by all means, I’m in favour of experimentation and seeing what works. Some challenges I see with mobile node wallets:

The need for mobile node channel management, rather than doing all the channel management on a home node. Arguably it ends up being additional sets of channels running if the user has to run a separate mobile lightning node(s) and a home lightning node.

Slower payment routing on mobile nodes.

Potential reduction in privacy and increased risk of payment censorship if using only one channel with an LSP, rather than doing your own channel management with multiple channels.

Mobile phones and apps often get lost or deleted, so backups are crucial to really make mobile lightning node wallets work nicely.

As I mentioned above, currently my preference is towards the ‘remote control your home node’ approach. I think a likely direction we will go down is one bitcoin/lightning node (could be a RasPi node or similar) at home for the family, with each family member remote controlling their own ‘account’ on that node while out and about, using apps such as Blue Wallet or Zap etc.

Abstracting away the details

In the Lightning Network, barriers to ease of use are being abstracted away with technical innovations. One example is the inbound capacity problem, where a user opens a channel outbound, but does not have any incoming capacity as the ‘beads of the abacus’ are already on their own side. Apps like Breez solve this with an inbound channel to the user to get started, so they can immediately receive funds via lightning. We are seeing progressive innovations and tech coming to create better outcomes for users and faster onboarding.

In terms of what is coming soon, we can expect more use of Turbo channels (a channel opened to the user where some of the balance is ‘pushed’ to the user’s side, so they may spend immediately). One announcement timed for this conference was Phoenix, a new Lightning app from ACINQ making clever use of a Turbo channel that doesn’t exist yet, but is created for the user once a lightning invoice is paid to fund it. Submarine swaps are used in the app for it to be able to pay bitcoin on chain, but remaining in lightning as a default.

We're very excited to introduce Phoenix, a 2nd generation Lightning Wallet. 🚀



Phoenix demonstrates what we think is the future of Bitcoin/Lightning UX.#TLC2019 #bitcoin #LightningNetwork pic.twitter.com/TumV3UKyf8 — ACINQ (@acinq_co) October 18, 2019

We should also be seeing AMP (Atomic Multipath Payments) relatively soon. AMP will help lightning users use routes going across multiple channels, which may mean less need for the user to manually do channel management. In practice from a wallet developer’s POV, this may mean even more detail can be abstracted away behind the scenes, so the user can get away with even less knowledge of what’s going on “under the hood”.

The customer can just see one unified balance, rather than having to see bitcoin balance and lightning balance / receive capacity. New fiat to lightning services are being made available such as Olympus (along with Zap), Sparkswap. I like that hodlhodl already has fiat to lightning capability, though this may be difficult for newbies to use if they do not have receive capacity.

Keeping it non custodial

I got the impression that most people at the conference were strongly anti-custodial wallets, which I agree with as the vision we should advocate, educate, and build towards. From a business POV custodial can become more difficult from a regulatory compliance perspective, and from a consumer POV non-custodial provides maximum sovereignty.

There was some discussion of how people will use custodial lightning wallets/services as part of packaged services and so on. My hope is that we treat custodial options as a ‘stepping stone’ to getting that user onto a fully validating, sovereign option where the user holds their own keys and runs their own node etc.

Where are we going with all this?

Elizabeth Stark’s session on Bitcoin as marathon was an interesting one also. To me, it really drove home this idea that we’re only getting started here! There were also talks and discussion about things like incentivising messaging with mesh networking, lightning journalism, and the use of lightning by exchanges and merchants. But on the whole, I found it so exhilarating to be there at the start of all this. Lightning as a protocol, and lightning products and services are rapidly iterating and improving!

Closing session for Day 1 with Elizabeth Stark and Jim Patterson

Photo credit: Enid Valu @WarmDefeat (see gallery here)

Special thanks to Jeff Gallas and the Fulmo Lightning team, all the volunteers, Elizabeth Stark, my co-MC Desiree Dickerson, the speakers, and the sponsors of the event for putting in so much work to make it all happen.

Make sure you subscribe to SLP to catch the episodes I recorded in Berlin with Alex Bosworth and Jack Mallers. If you want guidance on how to run your own lightning node, make sure you sign up for a Ministry of Nodes Webinar.