When it comes to blockchain technology, the application layer is where all the dapps live. The ethereum blockchain is home to a large and growing number of decentralized applications (dapps).
These dapps are what give the ethereum network its utility and value.
It is important to remember that all data on the Ethereum application layer is stored publicly and permanently on the blockchain. This means that any data sent to the application layer, such as transaction information, addresses and smart contracts, will remain there indefinitely. As such, it is highly recommended that users take extra caution when dealing with sensitive information or data on the Ethereum application layer.
The application layer is also where a lot of the innovation in blockchain is happening. There are dapps being built on ethereum that are trying to solve all sorts of problems, from providing a new way to social media to changing how we interact with the internet of things.
The application layer is also where much of the user-facing activity on ethereum takes place. If you want to use a dapp, you will likely do so through an interface that lives on the application layer.
So what exactly stays in the application layer of ethereum In short, anything that gives the ethereum network its utility and value lives in the application layer. This includes all the dapps that have been built on ethereum, as well as any user-facing interfaces for those dapps.