One of the amazing things that India has accomplished in the last few years is the UPI technology I would say. Being a software developer myself, I'm impressed by the way they handle the load on the servers and the way they provide a seamless experience to the users. From a technical standpoint, I might wonder what could be happening in the background but the best thing is that the users don't worry much about anything happening in the background and they continue to experience this without any issue.
Infrastructure
Infrastructure is the main thing here. The UPI interface should support several thousand users using the service at the same time. During some peak hours, there is also a high possibility that the service load can spike. I'm glad that they have handled this very well and they can continue providing this service without any technical issues or downtime. I'm sure the infrastructure is well-planned one and they have very good technical specs to handle this heavy load.
There are also new users starting to use UPI every single day and they can facilitate services for any number of users without any problem. This is an amazing thing.
Seamless user experience
As said earlier, the user experience is the most commendable thing here. Only a technical person can understand what can happen in the background. A Regular user will be worried only about the experience they get while using the app. Whichever application we use, it internally talks to the UPI interface and brings the data to us. When someone is sending the money the communication happens with the API and the API authenticates the user and does the transfer.
The transfer is pretty much instant and that's a wonderful thing. Earlier while using NEFT, things used to be slow and there was a slight delay during processing of the payment. IMPS was comparatively faster and today UPI is ruling the world with seamless experience where the transactions are pretty much instant.
UPI going global
Not only in India but UPI works in a few other countries as well and there are talks that a few other countries are also going to use this technology for their transactions. I have to say that it is best to share this technology with the world because we have seen the success of this technology in the last few years already and it is good to be leveraged in other countries too. People who are used to this payment method in India will also find it fruitful if it is available outside the country too.
Concurrency handling
The most important technical problem would be to handle concurrency. As I mentioned earlier, there will be more than a thousand concurrent transactions happening every second or every minute and sometimes the load can even be higher than that. The servers have to be powerful to handle the concurrency and there should be proper queueing done to queue the requests coming from the users and probably a way to complete those requests within no time so that even queuing shouldn't matter much. I'm glad that they are handling this very well.
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