API Lifecycle Management

API Evolution


Dheeraj Jaggi is the Head of API Engineering at NatWest in India. In this article, he discusses API evolution at NatWest.

Consider that I want to make a payment to a person. I have the person’s photograph with me. I choose that person’s face and send him or her money using the app. The app detects the face, gets the contact details for that person, and pays that person.

To make this transaction successful, there are four to five APIs that are doing the black magic; the first one is the one that registers the customers, and the second is the one that captures the UPI ID and validates it. The next one is the face detection API, followed by the face recognition API, recognizing and mapping the face to the UPI ID. Last but not the least is the payment API.

In 2018, NatWest started using APIs with open banking regulations. We have gone beyond the open banking regulations and created a digitized API-enabled bank. That means we have shifted from technologies to a culture where we think of API as a product rather than API as an interface that connects systems. In this way, we are helping our customers and partners to access banking services in their convenient ways. Besides banking APIs, we have created carbon calculator APIs and categorization APIs that help third parties identify and categorize transactions that carry an environmental impact. This is calculated based on how you travel, how much you travel, and the environmental impact. These carbon readings can be integrated with any third-party product.

We offer API solutions externally, but we also reuse APIs internally. NatWest acquired Rooster Money. The main challenge was around existing customers and their transition. We built three APIs to make it easier for them to onboard. The customer will be provided a login with the bank’s APIs that enable our customers to log in using their existing mobile banking credentials. Then, we used the cross-reference API, which helps connect these two apps using a common language. Then, we have the customer attribute sharing API. This enables data sharing, and the customer does not have to re-enter their data.

We have also empowered small businesses with direct connectivity to our services. For example, Free Agent is a third party that manages accountancy software for our customers. That means they provide tax solutions and help file tax returns for small business banking customers. This is possible because of APIs. We have also provided a feature for accessible funding via instant mortgages.

To manage this, we have focused on a durable cultural shift –

  • Product over project – We have to think about the whole API suite as a product and how the whole product can be aligned with the various third-party products.
  • Think externally – APIs should be available to the outside world as well.
  • Expect unseen reuse – Our suite has to be scalable and extensible.
  • Create once and curate – APIs should be reusable.
  • Be open – Try and have open-source APIs

We are opening ecosystems. We started with Open Banking in 2018 and moved to Open Finance in 2023. By 2026, we plan to move to Open Economy.

Open banking has been a qualified success. In the UK, there are 7 million active users, and those 0.7 billion monthly active users are in NatWest. That means approximately 10% of people. We have extended open banking’s impact by mandating use cases, commercializing APIs, and creating a multi-party system that brings competition, innovation, and collaboration.

We have to be where the customers are. Customers are becoming more expectant, which means they are enabled by technologies. They require personal offerings and unbundling of services. Winners can only come together if they break the traditional industry boundaries. We can offer unique capabilities that customers could value. Banks have an opportunity to leverage trust. Partnerships are reaping benefits in an increasingly interconnected economy.


Dheeraj Jaggi
Dheeraj Jaggi (DJ) an API enthusiastic & Evangelist and Head of API Engineer(India) within NatWest Data & Analytics. He manages the OpenBanking & API Platform from India location for the NatWest Group that includes building APIs for Third Parties Providers, conformance to OpenBanking (PSD2 & FCA) standards & regulations, Account and Payment Initiation APIs, Onboarding and Foundational Microservices. With many years’ experience in the banking and IT space, DJ has delivered many API Products to the market and passionately believes in the transformative power of APIs in any business unit or organisation.

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