Virtualization is a fundamental technology in cloud computing that maximizes hardware resource usage by creating multiple isolated environments, known as virtual machines, through a hypervisor. Originating in the 1960s with IBM's CP-40 system, virtualization has evolved into two main hypervisor types: Type 1, which runs directly on hardware, and Type 2, which runs on top of a host operating system. In the cloud industry, Type 1 hypervisors are prevalent due to their performance benefits. Modern advancements include Firecracker, a lightweight virtualization technology designed for serverless workloads, which uses Linux KVM to manage microVMs efficiently. Firecracker, written in Rust, provides secure, isolated environments with fast startup times and high density, making it ideal for serverless platforms like Koyeb. Containers have also become popular, offering standardized deployments with minimal overhead, though challenges in security and isolation persist. Firecracker addresses these challenges by combining the security of hardware-assisted virtualization with the speed and density of container technologies, positioning it as a key component in the Koyeb stack for enhanced serverless deployments.