I am designing an iOS app that receives multiple contact numbers from a server and sends messages to those numbers. I have made this service with an external API called Twilio, but Twilio costs(quite a lot actually if all my users are to send bulk messages). I want to make this App free for use and to make the user pay for the number of text messages they send, which will be charged by their carrier.
I found an app called 'Group SMS 4!' by Cedars and this app does exactly what I wanted. I'm sharing you the link for the app on the appstore
I've used the app, and I know it doens't use an external SMS gateway but MFMessageComposeViewController. But I though sending programmatically through iPhone restricted the number of texts sent to be less than 9 ~ 20 (depending on the carrier).
So my conjecture on how this problem was solved was,
- Divide the contacts in a group of 5~9 somehow and send them separately, and sequentially when send button is pressed
Was my guess correct? If not, What would be a way to achieve this? I just need the user to be able to send up to 100 people automatically and without hassle. Thank you in advance.