Rollup as a service is a solution that enables developers to deploy Ethereum Layer 2 scaling solutions known as rollups without having to deploy and manage their own infrastructure. Rollups are a type of Layer 2 solution that bundle many transactions into a single transaction, increasing the throughput of the Ethereum network. By using a rollup-as-a-service solution, developers can focus on building their applications without worrying about the underlying infrastructure, which can be complex and time-consuming to manage. Instead, they can simply connect to the rollup service through an API, enabling them to scale their applications more easily and efficiently on Ethereum.