"The beauty of this online trading platform is you can trade anytime, anywhere, on any device and in real time," he said.
It has an online calculator allowing farmers to calculate savings before registering.
"With this national online marketplace connecting all rural New Zealand, costs are reduced through direct transactions, value is gained through access to a wider market and relationships and knowledge are built across the whole supply chain. Everyone wins."
StockX was planned for five years by John Cannon and Andrew Russell.
Mr Russell is a fifth-generation farmer at 1400ha Tunanui Station in Sherenden and the director of logging and engineering firms.
Mr Cannon is an agribusiness consultant and award-winning farmer.
With sportsground.co.nz founder Mike Purchas on board and a $1.5 million share offer last year fully subscribed, StockX should fare better than past attempts to circumvent the traditional sale-yard process of trading stock.
It charges a flat fee of 2.5 per cent for all livestock transactions
By removing sale yards animal welfare was another advantage.
Mr Roebuck is the former CEO of Farmers Transport, now a division of South Island agribusiness HW Richardson Group.