What is the name of Bitcoin’s second-layer payment network for faster off-chain transactions?

The Lightning Network is Bitcoin’s second-layer payment network for faster off-chain transactions.

It uses payment channels, allowing participants to conduct multiple transactions without recording every payment individually on Bitcoin’s base blockchain. A channel can later be settled on-chain, while the network’s routing system can connect payments across channels. This design aims to reduce delay and transaction costs for suitable payments.

Lightning is not a replacement blockchain for Bitcoin, and it is not the same as a Bitcoin sidechain. Its channels use Bitcoin transactions and cryptographic contracts to manage balances. The network was described in a 2015 paper by Joseph Poon and Thaddeus Dryja. Actual use requires liquidity, channel management, and compatible software, so Lightning does not make every Bitcoin transaction instant or free. It is best understood as a protocol layer built to support smaller and more frequent payments away from the base chain.