Lightning Network basics

Lightning is a second layer built on top of Bitcoin for fast, cheap payments. Instead of broadcasting every transaction to the base chain, two parties open a channel and exchange signed balance updates off-chain. They only settle to the chain when they close the channel. Routing payments through a graph of channels lets anyone pay anyone else, often for fractions of a cent and within seconds. For users, the experience is just "tap to pay". For developers, it unlocks micropayments, streaming money, and machine-to-machine commerce that don't make sense on Layer 1.