In Open Systems Interconnection (OSI) Model, the Application Layer of the seven-layer Open Systems Interconnection (OSI) Model is the top layer that approaches protocols for application interaction with the network.
With a focus on end-user services, the application layer helps to facilitate process-to-process connections over Internet Protocol (IP).
Source: Application Layer
In Decentralized Finance (DeFi), the Application Layer as the name indicates, is where consumer-facing applications reside. These applications abstract underlying protocols into simple consumer-focused services. Most common applications in the cryptocurrency ecosystem, such as decentralized cryptocurrency exchanges and lending services, reside on this layer.1)