The app is executed in the execution environment as one or more processes.

Twelve-factor processes are stateless and share-nothing. Any data that needs to persist must be stored in a stateful backing service, typically a database.

The memory space or filesystem of the process can be used as a brief, single-transaction cache. The twelve-factor app never assumes that anything cached in memory or on disk will be available on a future request or job.

References

• https://12factor.net/processes