Ride-sharing service Sidecar on Monday said that along with transporting people it is making same-day deliveries of packages.

The San Francisco-based startup, whose list of backers includes British tycoon Sir Richard Branson, revealed that it has been experimenting with delivering flowers, groceries, hot food and other items in its home city for the past six months and is ready to expand the service nationwide.

Sidecar co-founder Sunil Paul said in an online post that he expected same-day delivery services to represent half the company's business by the end of this year.

"Our vision is that one day any business will be able to take an order and get it to the customer in an hour, and Sidecar will be the service that powers this capability," Paul said.

He said that moving people along with packages enables Sidecar to charge bargain delivery prices while getting items quickly to destinations.

"We're seeing explosive growth with same-day delivery already," Paul said.

Same-day delivery is running in San Francisco and will spread in coming months to other US cities where competitors Uber and Lyft operate, according to the company.