blog: hack inout 2019

content/blog/2019-10-25-paisavasool-hackinout-2019.md

++++
+title = "PaisaVasool - HackInOut 2019"
+date = 2019-10-25T15:30:03+05:30
+draft = false
+categories = ["projects"]
+type = "post"
+url = "blog/2019/10/25/paisavasool-hackinout-2019"
+author = "Rohan Verma"
++++
+
+Last weekend I attended a hackathon after a long time. HackInOut, which is
+India's biggest community hackathon, was happening very close to where I live. I
+went with my office colleagues [Vivek](https://vivekr.dev) and [Karan](https://mrkaran.dev) and we had discussed a lot of ideas before reaching the venue, 
+but we were not sure what we will finally end up building. 
+
+![hackinout2019](/images/hackinout2019.jpg)
+
+After discussing our ideas with Siddharth Shetty, an iSpirit fellow 
+and one of the mentors at the hackathon, we finally decided to build 
+PaisaVasool.
+
+![logo](https://raw.githubusercontent.com/CapsLockHacks/paisa-vasool/master/assets/logo.png)
+
+## What is PaisaVasool
+
+Split subscriptions and collect money automatically and instantly over UPI seamlessly.
+
+<iframe width="100%" height="480" src="https://www.youtube.com/embed/QyaZFz8StoQ" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>
+
+## The problem it solves
+
+Sharing subscriptions like Netflix friends is not seamless. Collect payments
+online and reconciling them manually using Apps still requires us 
+to manually confirm payments, and APIs/SDKs by PSPs are expensive. 
+
+## The hack
+
+We piggyback on paisa values in the UPI request amount as the transaction ID, 
+and reconcile the payment seamlessly and automatically into the subscriptions.
+
+## The app
+
+To demonstrate the hack for this hackathon, we decided to concentrate our efforts 
+to Splitting Recurring Payments such as those for 
+Netflix/Amazon Prime/Hotstar/Spotify etc. Although, our 
+hack can be extended to any kind of collect requests.
+
+A user can create groups on our app and enter his friends contact details
+and instantly get reconciliations from our app when he receives payments.
+
+### Our hack allows you to consolidate your UPI requests for free! 
+- Daily UPI requests are limited by PSP apps like Google Pay. 
+  - You can request upto 5 times on Google Pay a day
+  - New users can't be requested more than once a day
+- Payment API's are expensive
+  - Costs (2% per transaction) are added onto the consumers
+- You need to check your Bank transaction details and reconcile manually without a PSP
+- Apps like Paisa Vasool are impossible on top of UPI as of today
+
+### Our hack allows payers to pay with any VPA.
+- No need to ask your user to be on a specific UPI app
+- No need for payee to pay from his own account (parents/friends can pay on behalf)
+
+### Instant reconcilation
+- We process the transacation as soon as we get the bank SMS
+- Users don't need to check their bank details
+
+## Challenges we ran into
+
+The biggest challenge was to figure out a way to solve these issues:
+
+- How to identify a transaction
+- How to not need the payers VPA
+
+We figured out that:
+
+- The identifier can be embedded in the paisa value
+- We can read SMS to get the amount and parse the transaction ID.
+
+### Detailed technical flow
+- User installs our app and gives read permission for SMS to our app.
+  - Our app is open source and only sends SMS with UPI VPAs to our server
+- They create a collect request in the UI with the amount and users, and create a group for recurring weekly/monthly transactions.
+  - User adds his clients/friends to the group using mobile number and/or email
+    - These are saved for the future
+- The collect request is then processed by the server
+  - UPI link (which can be embedded in SMS/Whatsapp/Telegram) is created using [https://upi.link/](https://upi.link/) API - It is sent to all the clients/friends with appropriate amount that has been hacked to include the transaction identifier in the amount paisa value. 
+- The app waits for SMS from the bank of the User, which includes the amount (plus paisa value identifier) inside it.
+  - On receiving the SMS, we change the state of the pending transaction to complete.
+- The user can check the state and see all his transactions from our app.
+
+## Future
+- The [Sahamati framework](http://www.sahamati.org/) in the future will allow users to share their bank transaction ledger details with apps directly in a standardized format via Aggregators.
+- UPI roadmap has split requests planned for the future.