Onion Routing

This article is the first (out of two) concerning Onion Routing. It is also the first of the Routing Series, where I'll try to cover in depth how routing works in the Lightning Network, and how it could work differently (ever heard this story about an ant jumping on a trampoline?). This article is an introduction to Onion Routing, and offers a "high level" view of how it works. The second article will go deeper into the inner workings of Onion Routing in the Lightning Network....

February 9, 2022 · 14 min · Fanis Michalakis

What Are PTLCs

If the Lightning Network is so useful today, it is in great part thanks to the fact that payments can be routed inside the network: if Alice wants to pay Bob, it isn’t necessary that she has a direct channel with him. Instead, she can have a channel with Carol and, if Carol has a channel with Bob, use Carol’s channel to reach Bob. With this mechanism arises a new question: how can such payments, that rely on the benevolence of third parties such as Carol, be achieved in a trustless way?...

January 15, 2022 · 17 min · Fanis Michalakis

What Are Anchor Outputs

The last two “long” articles of this blog were dedicated to special kinds of Lightning channels that seek, each in their own way, to enhance the user experience on the Lightning Network. This week, we will dive into anchor outputs, which aim to ensure channel closings are settled quicly, even in the case of a force close. This article will go into details as to how Lightning works in this regard, what are the issues and how anchor outputs can solve them....

January 3, 2022 · 12 min · Fanis Michalakis


Today’s post was inspired by this very good question from @antward on Twitter: Millisats? I thought sats was the smallest unit? — Larix Lynx ⚡️ (@antwar) December 15, 2021 As you can see, I tried to give him a synthetic answer, but then I thought to myself: why not devote today’s short piece to this question? So here we are. 1 millisat = 0.001 sat That’s the shortest answer one could give....

December 16, 2021 · 4 min · Fanis Michalakis

What Are Hosted Channels

Last week’s article dealt with Turbo Channels. Today, I’ll cover Hosted Channels, another kind of channels that seek to enhance the Lightning channels UX while staying in line with the specification and mitigating the required tradeoffs. Not on-chain enforceable channels The big difference between a hosted channel and a regular Lightning channel is that the former is not enforceable on-chain, simply because there is no channel opening transaction to spend from....

December 12, 2021 · 6 min · Fanis Michalakis