Caching data

Hallo the app I am working on shows lets say a price list to the user.
I need to implement a sort of timed caching, so I’m thinking of this architecture:

  • a PHP backend periodically generating 2 JSONs:
  • a JSON containing actual data
  • a JSON containing an hash of the data and a timestamp

from the frontend, I’d go as depicted in the attached image

(I omitted the part about security and authorization just for clarity)

Am I overly complicating things?
Am I missing some helper / service / plugin / 3rd party something which already would help me achieving my needs?