Q:

SMS online sending service

I'm looking for an online sms sending service, that I can use within my iOS-App.
My aim is to send a verification code to the phone number, the user provided.
In Android its not too big of a deal, since I can send sms programmatically, but in iOS 
I can't. Any suggestions?

A:

In our app we use http://www.twilio.com/ to send SMS through a service on the iPhone, its pretty great. 
For sending SMSs you don't even need to download their SDK and put it into your project. It basically comes down to a HTTP POST command in which you provide the phone number to SMS, the message body, and your API key+secret.
Here is an example for your convenience on sending an SMS through Twillio:
- (void)twilloSendSMS:(NSString *)message withQueue:(NSOperationQueue *)queue
           andSID:(NSString *)SID andSecret:(NSString *)secret
    andFromNumber:(NSString *)from andToNumber:(NSString *)to {
    NSLog(@"Sending request.");

    // Build request
    NSString *urlString = [NSString stringWithFormat:@"https://%@:%@@api.twilio.com/2010-04-01/Accounts/%@/SMS/Messages", SID, secret, SID];

    NSURL *url = [NSURL URLWithString:urlString];
    NSMutableURLRequest *request = [[NSMutableURLRequest alloc] init];
    [request setURL:url];
    [request setHTTPMethod:@"POST"];

    // Set up the body
    NSString *bodyString = [NSString stringWithFormat:@"From=%@&To=%@&Body=%@", from, to, message];
    NSData *data = [bodyString dataUsingEncoding:NSUTF8StringEncoding];
    [request setHTTPBody:data];

    [NSURLConnection
     sendAsynchronousRequest:request
     queue:queue
     completionHandler:^(NSURLResponse *response,
                         NSData *data,
                         NSError *error)
     {
         NSHTTPURLResponse *httpResponse = (NSHTTPURLResponse *)response;
         if ([data length] >0 && error == nil && ([httpResponse statusCode] == 200 ||     [httpResponse statusCode] == 201))
         {

             NSString *receivedString = [[NSString alloc]initWithData:data encoding:NSUTF8StringEncoding];
             NSLog(@"Request sent. %@", receivedString);

     }
     else {
             NSString *receivedString = [[NSString alloc]initWithData:data encoding:NSUTF8StringEncoding];
             NSLog(@"Request sent. %@", receivedString);
             NSLog(@"Error: %@", error);
     }
 }];
}

