The front end uses the ci framework of php used by vue and the back end. How do the front and back ends cooperate in development?

  question

The front end uses the ci framework of php used by vue and the back end. How do the front and back ends cooperate in development?

According to our practice in more than ten projects, the back-end api interface is currently developed, and the json specification is used for front-end and back-end interaction.
This is an add interface:
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