Mkuu nimeona ume-concentrate sana na MPESA API, I don't see the big deal here, I mean MPESA API mbona kazi ndogo, na am sure wapo wabongo wengi ambao washawahi ku-experiment with it.
Mimi mwenyewe nshawahi tafuta solution coz nilitaka kuintergrate my app to MPESA, Vodacom wanazingua, wanatoa majibu ya juu juu tu as if they don't care, na most of the times wanataka pesa. Ofcoz hata wakitaka niwatengenezee ni kitu simple tu coz tayari they have a database yenye all the transaction details.
Solution nzuri tu ya pembeni na nyepesi sana kuimplement, raspberry pi iliyo connected kwenye internet 24/7, weka modem na line iliyo-connected na MPESA account yako. Mtu akilipa message inaingia kwenye raspberry pi, unaandika script nyepesi ya kuhakikisha kua message imetoka Vodacom na sio kwingineko, una-parse all the required information namba ya simu ya aliyelipa, kumbukumbu namba, amount, tarehe, unatuma hiyo information kwa POST request kwenda kwenye the main server ambayo ina-authenticate kwa TOKEN kua ni kweli message imetoka kwenye raspberry pi yako na sio kwingine, then una-save that information kwenda kwenye database.
Simple na haina risk ya security threats.. The only problem utakayoface ni kama machine yako inayo-listen for incoming messages itaenda offline. Na sio lazima raspberry pi, hata ukiweka line kwenye simu na kutengeneza a simple android/iOS app inayolisten for the messages still inapiga mzigo vizuri tu.
This works quite well kwa almost any application bongo since hata kama ni watu wanalipia hawatokua in millions at the same time kwa hiyo it can handle the load. For very big application itakulazimu tu ucheze na backend Vodacom moja kwa moja coz they can't send you a million messages in a single day. Ila na yenyewe it shouldn't be something very hard to implement, am sure Vodacom wana server kubwa tu, wakimpa programmer yoyote aliye serious access kwenye system anaweza tengeneza, so yah! many Tanzanians can make it.