Another startup in India is cashing in on the popularity of WhatsApp, the most popular app in the country with more than 400 million users, to build a business around it.

Digi-Prex is a seven-month old startup that runs an eponymous online subscription pharmacy in Hyderabad and serves patients with chronic diseases. Patients share their prescription with Digi-Prex through WhatsApp and the startup’s workers then deliver the medication to them on a recurring cycle.

Delivery is not the only thing Digi-Prex is trying to provide. It helps patients better track when they need a new supply of medicine, and checks if they are seeing improvements. The startup has amassed thousands of customers in Hyderabad, Samarth Sindhi, founder of Digi-Prex, told TechCrunch in an interview.

Digi-Prex just closed its seed round from a range of highly-influential VC firms. It’s also one of the largest seed financing rounds for an Indian startup.

The startup has raised $5.5 million from Khosla Ventures, Vedanta Capital, Y Combinator, Quiet Capital, and SV Angel. Justin Mateen, a founder of Tinder, also participated in the round, said Sindhi.

“Instead of trying to acquire customers online, we work with physicians and pharmacies to serve customers,” said Sindhi, an alum of Brown University who worked with a healthcare firm in the U.S. before returning to India. The startup shares some margin with physicians and pharmacies, but more importantly, it says this arrangement works for everyone because it is able to serve customers who are living at distant neighborhoods.

Digi-Prex works directly with medicine distributors to secure supplies at lower costs. It then undercuts the pricing of over-the-top counters, providing medicines to its customers at discounted rates.

Sindhi said the startup will use the fresh capital to expand its business to 10 cities in India, and find ways to be more useful to the patients. Some of the things that Digi-Prex is working on includes providing patients with access to better physicians and offering them more information about their disease.

It’s not surprising why Digi-Prex is using WhatsApp as a distribution platform. “When I returned to India, I was fascinated by how nobody was texting anymore. Everyone was doing everything on WhatsApp,” he said.

WhatsApp, which is already the most popular app in India, is increasingly finding business applications in the country. Vahan, another Y Combinator-backed startup, is using WhatsApp to help blue-collar workers find jobs with logistics companies.