An application-sized environment
Containers package an application and its userspace dependencies into an isolated environment. Unlike a virtual machine, a container shares the host’s operating system kernel. This makes a container a useful unit of application deployment, but does not make it a replacement for every virtual machine workload.
Isolation and allocation are different
An isolated filesystem does not describe the amount of memory or CPU available to your application. Resource limits are separate controls. Before choosing a plan, check memory, CPU scheduling, storage persistence, network policy, and supported access methods.
Start with the workload
A small API, a stateful database, and a background worker have different requirements. Choose based on measured usage and operational needs. Leave space for startup, builds, cache growth, and the traffic you cannot predict.
Explore the handbook or compare the sample plans.