What is a Bitcoin Layer?

A Bitcoin layer is a solution built on top of the Bitcoin mainchain to increase the network programmability and scalability. Since layer 1 blockchains have limitations in maximizing decentralization, security, and scalability, additional protocols can be developed to expand utility. Examples of Bitcoin layers include Lightning Network, Stacks, RSK (Rootstock), and Liquid Network. These layers bring more use cases to Bitcoin, such as smart contracts, decentralized applications, NFTs, DAOs, and other Web3 infrastructure.