An application chain is an independent blockchain built specifically for a particular application or function. It has its own consensus mechanism, governance structure, and resource allocation, and typically maintains interoperability with other blockchains. The design goal of an application chain is to optimize the needs of specific applications, such as improving processing speed, reducing transaction costs, and enhancing security, in order to address resource competition and congestion issues on public blockchains. However, compared to protocols, application chains have the disadvantages of high technical requirements and poor composability and interaction.