Cloud

An application that assumes a particular machine, a particular filesystem or a hand-configured environment is expensive to move and expensive to scale. Following emergent standards, defining clean contracts and coding against them is what keeps an application portable between execution environments — a laptop, a CI runner, a container platform, a managed runtime.

Two conventions do most of that work. The Twelve Factors set out how an application should treat its codebase, its configuration, its processes and its logs so that any environment can run it unchanged. The Open Service Broker API covers the other half of the contract: how a platform provisions the backing services an application attaches to, and how it hands over the credentials.