Hi There,
I checked your post and Here are the answers to your questions:
1) Api is data manipulation on third party which use by only authorize user using authentication token (unique value for one time )
2) api need input parameter with authorize user
3) api can fast access without write full functionality at our server, we can only call and get response
4) using pagination , compressing data and reducing number of request on api server
5) authentication and using post method of api and using inherited methods
I would like to discuss further on this, Please message me for more discussion.
Thanks and Regards:
Albert