gistfile1.m

NSMutableURLRequest* request = [[NSMutableURLRequest alloc] initWithURL:"http://127.0.0.1/test"];

[request setHTTPMethod:@"POST"];
[request setHTTPBody:[@"{json:goes, here:0}" dataUsingEncoding:nSUTF8StringEncoding]];
[request setValue:@"application/json" forHTTPHeaderField:@"Content-Type"];

NSURLConnection* conn = [[NSURLConnection alloc] initWithRequest:request delegate:self];

[conn start];

//Then implement the delegate methods on self
// Defined here: https://developer.apple.com/library/mac/#documentation/Foundation/Reference/NSURLConnectionDelegate_Protocol/Reference/Reference.html#//apple_ref/occ/intf/NSURLConnectionDelegate