According to the Twelve-Factor App methodology, what is a backing service?

According to the Twelve-Factor App methodology, what is a backing service?
A . A packaging service for distributing support libraries.
B . A service that stores user session data in memory of the application.
C . A service that creates an in memory shadow copy of an application for redundancy.
D . A service consumed by an application over the network as part of its normal operation.

View Answer

Answer: D

Explanation:

A backing service is, basically, any networked attached service that your application consumes to do its job.

This might be a MongoDB instance, PostgreSQL database, a binary store like Amazon’s S3, metrics-gathering services like New Relic, a RabbitMQ or ActiveMQ message queue, a Memcached or Redis-based cache, an FTP service, an email service or indeed anything else. The distinction is not so much what the service is so much as how it’s exposed and consumed in an application.

References: https://dzone.com/articles/12-factor-app-style-backing