Vogue editor Anna Wintour, actor Bradley Cooper and Vogue editor-at-large Hamish Bowles at Burberry Womenswear at London Fashion Week.

FORTUNE — Not long ago, making a seating chart for a fashion show was a pretty ugly process. A master plan hashed out in New York might be faxed halfway around the world to a designer for approval, where it would be marked up and sent back half a day later. Last minute additions to the guest list were made by hand; RSVPs were collected by phone.

“We were using so much paper, and time efficiency was also an issue,” said Rachna Shah, the executive vice president of KCD, a fashion publicity firm that helps organize runway shows for major labels like Calvin Klein PVH and Tommy Hilfiger.

Then the fashion world met Eddie Mullon. In 2004, Mullon arrived at KCD’s New York office to extract a virus from a publicist’s computer. (The company found out about the Malawi-born, Britain-bred computer repairman and software developer through flyers he had posted around the city.) He became a technology consultant for the firm and watched them struggle to figure out who would sit where at the dozens of shows they organized in New York, London, Milan, and Paris twice a year.

“They would have 50 people working on a document, taking a picture, scanning it down and faxing it to Paris,” Mullon recalled. “I said, ‘I could do this on a computer. It would be like a video game.’”

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This was the genesis of Fashion GPS, a platform that creates seating charts for the majority of mainstream, high-end fashion shows, which can each generate hundreds of millions of dollars in economic impact. Mullon built proprietary software that allows multiple show organizers to work on a chart at once — think of it as Google Docs for the fashion set.

The Anna Wintours and Kanye Wests of the world can be dragged and dropped into their appropriate seats, and seating assignments can be changed in real time at the event via an iPad app, “depending on who turned up and who didn’t,” Mullon said. For show-goers, he developed GPS Radar, a smartphone app that keeps track of invitations, seating assignments, and gets updated with the latest images of what’s gone down the runway. He has also experimented with airport-style check in kiosks and RFID tags, which he embedded in the paper invitations for Christian Dior’s latest show in Paris, allowing attendees to breeze past receptionists with nary a pause in their stiletto-ed stride.

“The way that Europe works, they want an invitation that’s physical,” he said.

For designers, Fashion GPS has been “game-changing,” said Aliza Licht, Donna Karan’s senior vice president of global communications. “We used to have to e-mail each guest with his or her show seat assignment number. Now we can send seat assignments to five hundred people at the same time in one click.”

And though fashion favors form in nearly every other regard, for Fashion GPS, functionality has been a boon. “From every standpoint, it’s made the process more efficient,” said KCD’s Shah. “It’s allowed us to focus on other things, as opposed to just who’s sitting where.”