Apple's documentation is pretty good in this regard. Network comms are generally done using URLSession: https://developer.apple.com/documentation/foundation/ur

Apple's documentation is pretty good in this regard. Network comms are generally done using URLSession: https://developer.apple.com/documentation/foundation/urlsession https://developer.apple.com/documentation/foundation/urlsess... Reading files is most often done using the String and Data types: - https://developer.apple.com/documentation/foundation/nsdata/1413892-init https://developer.apple.com/documentation/foundation/nsdata/... - https://developer.apple.com/documentation/swift/string/init(contentsof:encoding https://developer.apple.com/documentation/swift/string/init(...:) I've found Apple's documentation for Foundation to be quite exemplary.