Greenlight is an attempt to onboard new users to Lightning without giving them all the burden of it from the beginning. The goal is to provide a first onboarding onto Bitcoin ecosystem running the node for the user until he is ready to graduate to self-hosting.

End-user nodes usually check it 3-4 times a day, so the idea is to have node spinning up just once the user comes online to use the node. Optimization was done on start-up, spinning up in 1s, connecting to peers in a couple and be ready in a short amount of time. Always-on is an illusion.

Core-lightning architecture: - Main daemon: lightningd - Sub-daemons: hsmd, gossipd, connectd, etc. - Plugins: arbitrary scripts to customize the node. This follows UNIX philosophy: "Do one thing and do it well".

Blockstream runs many nodes, with no control on any of the funds of the user, nor of his keys: It's a VLS signer on the user side that talks to hsmd through a proxy to use the node.

On a daily basis, Blockstream consumes around 72 TiB/day of data from the main chain to keep all the nodes up-to-date. This is done on just two bitcoind instances!