The company, which made a profit of £12.2m in the last financial year, said open standards had allowed it to exploit parent company Tesco's existing IT infrastructure.
"Using existing strengths, such as IT infrastructure, was one of the most important factors behind our success," said Jon Higgins, head of e-commerce development at Tesco.com. "The investment we have made over the years on IT is pitiful when you compare it to the return on investment we have gained. Taking an off-the-shelf package when you already have something suitable will only cause long-term pain."
XML and web services have allowed Tesco.com to avoid having to install new systems, said Qusai Sarraf, chief executive at e-commerce firm Ivis, which is the retailer's technology partner.
"Open standards allow you to plug in various modules - it is how you really drive ROI," he said. "The key lesson to learn is to start slowly - Tesco.com started with the absolute minimum, both in terms of technology and business requirements."
Tesco.com has also used XML to support its non-food web offering, National Store.