Besides bringing convenience to the commuting public, it has also helped create jobs for hundreds of vendors across the country who are now a common sight at bus ranks with their colourful vests.
Zupco, in partnership with NMB Bank, introduced the tap-card last year in January, with more than 90 percent of the commuting public now using them.
The money is prepaid and this has helped many people in budgeting and has also made life easier for conductors as they do not move around with wads of cash.
A card is being sold for $15 and commuters can top-up with whatever amounts they want.
The card can also be used to buy goods through the point of sale machine from shops and service providers. Zupco charges $2 for local trips, while they also have the cheapest fares for long distance buses.
Kombis in most cities charge between $5 and $15, depending on the distance and many of them demand cash payments. With a fleet of close to 500 conventional buses and 526 kombis, Zupco is now the largest public transporter in the country.
The company's chief executive officer, Mr Evaristo Madangwe, said their aim was to acquire more buses to ensure that all areas of the country were serviced.
"The tap-card which we introduced in partnership with Harare Institute of Technology, NMB and CBZ banks is proving to be popular with passengers," he said.
"We are now left with a few provinces where the system is still to be introduced.
"We know that many people are not accessing cash and the tap-card has come as a big relief. We encourage people to frequently use these cards because if you do not use it for two to three weeks it will be deactivated."
Mr Madangwe said the system was designed to secure the money paid.
"Once one pays his or her money, it is secured while no charges will be effected on the use of the tap-card," he said.
Mr Madangwe said if the tap-card was deactivated, it can be reactivated after payment of a dollar. Director of technology at Harare Institute of Technology, Dr Talon Garikai, was recently quoted as saying the tap-card system was part of a new engineering model to manage large fleets.
The tap-card was developed and designed at the institute.
"The monitoring system will allow for remote real-time monitoring of routes through satellite imaging, as well as location specifics of physical surroundings of the bus routes," said Dr Garikai.
"At the moment, the system is in the first phase and we are in the process of upgrading it to integrate normal banking services for the convenience of users.
"The card has no transaction fee and this can be controlled on one's phone. In the second phase, the card will be used as any other electronic card, even for other transport operators and we are pushing this to be a national policy."
Dr Garikai said the new system would allow monitoring of the payment remotely by all depots. One of the vendors at Simon Muzenda Street Rank in Harare, Ashar Mukone, said the tap-card was a game changer, as many people now opt to use it instead of moving around with cash.
"In Harare Central Business District alone, I think there are more than 100 people selling these tap-cards," he said.
"We are paid on commission and their introduction helped in creating jobs for some of us.
"Those who possess the tap-cards usually get first preference in boarding Zupco buses. "Even when there are a few buses on the road due to fuel challenges, rides for tap-card holders are guaranteed.
"For just $100, one can travel 50 times on Zupco buses, as there are no extra charges."
Ms Sofia Joma said at first she did not see any value in the tap-card, but she has since bought three more cards for her children.
"At first I thought this system will not work, but I have realised that it is very convenient," she said.
"I can now budget my money and my school-going children are also enjoying this facility.
"We hope Zupco will continue rolling out more buses and replace some of the ageing fleet. The company should also come up with timetables like what used to happen in the past."
