As India moves to roll out one of the world's biggest vaccination drives, an app called CoWIN (Covid Vaccine Intelligence Work) will be the "backbone" of the exercise.
The vaccination drive comes with a whole set of challenges, including the seamless movement of the vaccines to vaccination centres, storing them at the right temperature and identifying beneficiaries in order of priority, all of which can be difficult even in countries with smaller populations.
But India, not lacking in technological prowess, is banking on the app to ease the process.
In Mumbai, the authorities have registered 225,000 health workers and front-line staff, including police officers, on the CoWIN app. "It is working good. All technical glitches can be sorted out and staff will get hands-on practice. (The app) is easy to use. Sometimes the Internet connection is slow or it doesn't accept data in a particular field," said Mr Suresh Kakani, additional municipal commissioner of the area's local administration.
He noted that without this technological intervention, the complex process would have been laborious and even more complex.
The Mumbai authorities, which intend to vaccinate 125,000 people in the first 12 days, have planned a final dry run for the app before countrywide vaccinations start today.
Through the app, the authorities will send an SMS to those who have registered to come to a particular centre to get vaccinated. They will use the app to track each dose of the vaccine, how many are in stock, and even storage temperatures. The app can also help ensure recipients get the two doses on time.
The app is an extension of the Electronic Vaccine Intelligence Network software developed with the United Nations Development Programme India and an international organisation called Gavi, the Vaccine Alliance.
Mr Ram Sewak Sharma, chairman of the government's Empowered Group on Technology and Data Management, said that "robust, dependable and agile technology shall form both the foundation and the backup for the country's Covid-19 vaccination".
The app, accessed only by the authorities till now, is likely to be released today, Indian media reports said.
India is the second-worst affected country, after the United States, in the coronavirus pandemic, with more than 10.5 million cases. But its number of new cases daily has been on a downward trend since the peak last September, with 16,946 on Wednesday.
Vaccines being distributed include one by AstraZeneca and Oxford University, and another by local firm Bharat Biotech in collaboration with the Indian Council of Medical Research's National Institute of Virology.
Efforts are on to fine-tune CoWIN as fake apps have surfaced. The Health Ministry last week warned users not to download the fake apps or share personal information on them.
Experts said India was well prepared for the vaccination drive with its experience of massive exercises such as national elections.
The near-universal use of Aadhar, an identity card with biometric details, address and phone number, is expected to help the government pinpoint recipients.
"It's a mind-boggling task," said Mr Arvind Singhal, chairman of management consulting firm Technopak Advisors. "But there is a well-oiled machinery in place with lot of elements used for vaccination. I think India has built technological strengths for this."