I'm an HDFC Bank user from last more than 15 years, and here is how many times I have used its payments app PayZapp: a grand total of zero. Despite 10 million downloads on Google’s India Play Store, there are probably many who haven’t even heard of the app, much less used it. As for those who have used it? User reviews on the Play Store have often flagged a buggy interface and slow performance. So it isn't surprising that HDFC is revamping the app. The Reserve Bank of India (RBI) fully lifted the restrictions on the bank's credit card operations and its planned digital activities only last week, after a spate of digital outages in 2020. Starring front and center in HDFC’s consumer-facing efforts is Zeta, a seven-year-old banking technology firm that has previously worked with banks such as RBL Bank, Axis Bank, and IDFC First Bank. The company is not only rebuilding the app but is also building out a second credit-card issuance platform. Landing HDFC as a client isn’t just a matter of pride for Zeta. The project, which it snagged around a year ago, remains Zeta’s biggest in the banking segment to date. The size and scope of the project has also helped the fintech raise a sizable round from investors like SoftBank. On the flip side, the very same size and scope are forcing Zeta to spend a big chunk of its workforce in the country on the project, ceding other opportunities to rival fintechs. Meanwhile, timelines have been delayed, and Zeta has nothing to show for its efforts yet. The company has ambitious plans beyond the HDFC project, but it has also put all its eggs in the HDFC basket. For the country’s largest private lender, Zeta is just one of a handful of moving parts that HDFC is currently juggling.