When putting together an application featuring airtime topups the choice between sync and async is not a trivial one. Here you can read about the differences between them and how to choose the one that better fits your needs
When making topups using Reloadly you have two options: syncrhonous or asynchronous. Unitl recently, going async meant a penalty on your server resources, since you had to keep polling Reloadly to get a status update.
Not anymore. Read here for details on how to be notified once the operation has finished.
