The advantage the paybill SIM has over the IPN method is that the transaction is &#39;true&#39; realtime i.e. the moment the sender has received the MPESA text, your modem has also received a copy. The downside is scalability - I wonder how many transactions you can pull with such a device over time. I&#39;ve used the SIM with a Cinterion modem (reading with Perl) and it was working fine but has issues with concatenated texts where a transaction takes 2 mem slots. Other issues to consider include stability of the modem...Cinterion is a good brand but once or twice it has hanged on me thus having to log in to MPESA and manually make entries...and run to the remote site for a cold reboot...you get the drift. If you push many transactions a day you definitely don&#39;t want this.<div>

<br></div><div>The IPN avenue is the best IMO - once you&#39;ve ironed out the duplicate messages it&#39;s fine. Messages hit your db in ~5 min after the sender receives the MPESA text. Another problem (for some transactions) is that you&#39;ll run into the 160-char limit they impose on the IPN texts - so if you want to parse the text to know your utility balance it can be a PITA. I don&#39;t really understand why they do this. With some code that reads over the previous entries in the db to intelligently reconstruct the balances, that shouldn&#39;t be much of a hassle.</div>

<div><br></div><div>My wish is that they implement JSON responses :)</div>