To get safe data when U make a get request from an api , a subsystem will check if the data check some requirements (the size , the type , the length , the form and more) to filter out any harm software
You're referring to data validation and filtering, if I'm not mistaken, to ensure that the data received from an API via a GET request is safe and reliable.
@camarie can provide more information on this.
Regards
I'm not sure what is the question here. The response of a HTTP request, email body etc. can be filtered, sure, although I am not sure how this affects various HTTP headers. One can assume nothing, though, and check the various returned data (Content-length, Content-type etc.) in order to be sure the response is correct (or not) and proceed accordingly.
