Interceptors | Fusion | Zeta

Interceptors 101: A definitive guide

Jun 09 - 2020

Interceptors (an offering of the Fusion platform) are HTTPS endpoints with the extra functionality of returning a response. Before we get to understand how they work and their use-cases, let’s take a look at a typical payment lifecycle.

A payment life cycle starts when the payer triggers a payment request via a payment instrument (Card, UPI, etc). The payment network (NPCI, VISA, Mastercard, etc.) then routes this payment to Fusion. Fusion goes on to transfer control to the fintech using interceptors. The fintech determines the fate of the payment and passes the control back to Fusion; and upon processing the payment passes the allow/disallow message to the payment network.

With interceptors, fintechs can take control of the payment authorisation by plugging in their business logic in the payment path. Fintechs determine the fate of the payment (success/failure) and notify Fusion on the same. Based on this response, the payment is processed by Fusion.

What are interceptors?

What are interceptors | Zeta

As mentioned above, an Interceptor is a simple https end-point that can accept the payment object along with a callback URL. The callback URL is expected to be invoked with the decision to allow or disallow the payment.


Interceptors can be configured at various states of a payment transactions

Interceptors: Use cases for fintechs

With the help of interceptors, the Fusion platform can solve a myriad of business needs for fintechs. Here are a few examples:

1. Just-in-Time (JIT) funding using interceptors

JIT Funding | Interceptors | Zeta

Let us consider a fintech company, CreditLine Inc. CreditLine Inc. is based out of Bangalore and gives its customers a credit line based on their profile. Rahul is given a credit line of ₹10,000. Currently, he has ₹1,000 in his prepaid account and this account is linked to the credit line issued for on-demand funding. Rahul is looking to buy a phone, and he can get his favourite model for ₹10,000 only. He decides to use his credit line to make the purchase.

CreditLine Inc. has configured an Interceptor with the help of the Fusion platform.

Rahul initiates the payment transaction through an e-commerce platform. When the payment reaches the state at which the interceptors have been configured by CreditLine Inc., the control is relayed to them. The endpoint provided by CreditLine Inc. is called upon with the details of the payment transaction. An internal check confirms that Rahul has an unutilised credit line of ₹10,000. A transfer of ₹9,000 ( ₹10,000 (Value of Payment transaction) -₹1,000 (Balance in Rahul’s account)) is made to his account so that the transaction can be processed. His credit line is reduced to ₹1,000.

Fusion is notified that the transaction is a success and then with the help of a switch processes the payment. A switch is an independent entity that assists in communication between various providers and performs a payment and settlement process.

2. Risk management using interceptors

Risk management | Interceptors | Zeta

In this use case, the fintech has a risk management system in place. By using interceptors, a payment can be paused, giving the fintech an opportunity to make a risk assessment for the payer, and respond with a failure message to Fusion. Thus, keeping risky transactions and delinquency behaviour of their account holders in check.

3. Multi-account payment using interceptors

Multiple accounts can participate in a payment transaction via interceptors.

For example, Rahul and his wife have a credit line of ₹10,000 and ₹15,000 and individual balances of ₹1,000 and ₹2,000 respectively. They are looking to buy a washing machine worth ₹15,000 and can use both credit lines to make the purchase. The amount of ₹10,000 is transferred to Rahul’s account (account balance: ₹11,000) and ₹2,000 is transferred to his wife’s account (account balance: ₹4,000). The amount is debited from both accounts and their credit line’s are adjusted accordingly.

All interceptor notifications sent by Fusion are fully encrypted and secure. In addition, fintechs can configure webhooks for real-time payment transaction data. 

Fusion is an API-based platform-as-a-service offering for Fintechs. The platform allows for fintechs to solve a variety of use cases as well as accelerating their go-to-market. 

To learn more about interceptors, please refer to Fusion’s documentation

Stay up to date on the latest in fintech