Area of responsibility, back-end developer when building RESTful APIs?

Please help in clarification of the issue. Tell the newcomer about the problem of back-end developer when building RESTful APIs. His area of responsibility. It is clear that the more experience and practice is good, but I want to know the minimum for back-end and where is the watershed and then there is the task of the front-end. Do I understand correctly that, in fact my main goal when building is to write code so that when requests to the server - the server gave information in the proper format in accordance with logic that is designed, father-in-law into practice this enter the address in the browser and leaves you naked json.
It is clear that there is also API access authorization authentication but it do not take into account.
April 19th 20 at 12:32
1 answer
April 19th 20 at 12:34
http/https
json
Some web server minimum to start for debugging
Some programming language
Some MVC framework
Minimal knowledge of major security threats for web. (You can take a list OWASP)

Still some little things like Url encoding
The Http encoding

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