Befitting the local culture, the engine powering Silicon Valley-based Tesla Motors’s disruptive drive through the auto industry is software-based. The automaker is counting on a home-grown software system, developed by CIO Jay Vijayan and his team of engineers, to support its direct sales efforts in the U.S. and handle anticipated growth in China and other markets worldwide.

The system, called Warp, is a combination of e-commerce and back-end management software and completely customized to support Tesla’s counter-approach to selling and servicing cars. The automaker uses its Warp-powered e-commerce website and its own showrooms, not dealerships, to sell cars. Warp also handles all the back office functions for Tesla such as order processing, supply chain management, manufacturing workflow management, financial accounting and lead management.

Tesla CIO Jay Vijayan

Telsa’s direct-sales approach, unique for the industry, means that the automaker, and not dealers, also handle customer service issues and that’s where the true advantage of having such a tightly-integrated software comes into play, Mr. Vijayan tells CIO Journal.

Through Warp customers request services and fixes, often software-based owing to the way Tesla cars have been designed. Mr. Vijayan recounted one example where a customer requested a fix for the fact that his car, when stopped uphill at a red light, would roll back slightly just as he pressed the accelerator when the light turned green. Through the Warp system, that request flowed back to engineers which created a fix to the braking system which was then delivered as an over-the-air firmware update to all Model S owners at the end of March.

Mr. Vijayan, who owns a Model S, said he received a notice on his car’s touchscreen that the update was available. He scheduled his to happen at 1:00 a.m. and the next morning when he went to his car, he now has the Hill Start Assist feature. Mr. Vijayan said he did not know of any other vehicles where adjustments to the braking system could be made over the air, without having to bring the vehicle into a service center.

That kind of customer feedback loop was what Tesla CEO Elon Musk envisioned from the beginning, said Mr. Vijayan. It’s one of the reasons that Tesla owns its own showrooms, runs orders through its website, and doesn’t work with dealers. “With dealers, the customer feedback doesn’t go that quickly or easily,” said Mr. Vijayan.

Tesla has battled with U.S. auto dealers in New Jersey and other states. Legislators in Missouri last week made an amendment to a state senate bill to prevent the sale of vehicles direct from a manufacturer. Dealers fear they could be cut out of existence in direct-to-consumer sales.

Analysts say the biggest risk with a company building its own back-end software is that it may not scale well as the company grows. Tesla now has about 155 retail locations globally but hopes to grow to have about as many retail locations as Apple Inc. over the next few years as it expands into China and other locations.

Mr. Vijayan says he’s confident the software can handle the growth. His team built it using the C# programming language and the .NET Framework Platform from Microsoft Corp. The initial software was built in four months with 25 software engineers and it went live in July 2012. The software runs on a private Tesla cloud and the team continues to add new capabilities. So far, it has successfully accommodated growth as the company went from annual revenues of $204 million in 2011 to more than $2 billion in 2013. It has also handled increasing daily volumes on the website from about 500,000 page views per day in early February 2012 to 35 million in August of 2013.

Write to rachael.king@wsj.com