From the far south side of Williamsburg, under the bridge and all the way to the tip of Greenpoint, this year’s New York City Marathon was one big block party for the trendy neighborhood. Nearly every corner featured a live DJ or indie band performance, and crowds of young, impeccably dressed Brooklynites clustered together mid-day to dance along to the music and support runners.

At certain points, interludes in dances moves were punctuated by the all too familiar pauses to check an iPhone, which were followed by hurried shouts that the runner was nearby. For some spectators, their smartphones served the purpose of tracking their favorite runner.

Steven Schafer. stood curbside on Bedford Avenue and North 10th Street tracking the progress of his girlfriend, who was steadily coming up the avenue, as indicated by a moving blue tag. He had flown in from London that previous Friday to surprise her, and meet with her mother, who flew in from Iowa to cheer her own. They had been excitedly tracking her progress on the 2015 TCS New York City Marathon Mobile App, which detailed not only where the runner was, but also noted her pace in real time throughout the marathon.

“We could watch her run through the neighborhoods this morning over breakfast,” he said. “When she started coming up Bedford Ave we knew we had to find a spot on the sidewalk.”

Some spectators held signs that had one general message of support on one side and a personalized message as their friend or family member breezed by. One group of women hailed down their favorite runner with an iPad mini, the app opened as the runner moved up the block and she stopped briefly to hand off the sweatshirt tied around her waist.

The app is powered by Tata Consultancy Services (TCS), which became the new partner and title sponsor of the New York Road Runners (NYRR) this past year, after supporting the marathon as a technology consulting partner since 2010. TCS is an Indian multinational IT service, consulting and business solutions company that operates in 46 countries and is one of the biggest companies in India. In a 2015 Forbes “World’s Most Innovative Companies Ranking,” TCS was ranked 64th overall, making it amongst the highest ranked IT companies on the list based on revenues.

But beyond expertise, the partnership between TCS and NYRR runs deep. The company’s CEO, Natarajan Chandrasekaran, “Chandra,” began running later in life, and has run five marathons, according to the NYRR website which proudly proclaims, “He’s one of us.”

The app TCS created allows supporters to track their favorite runners live with splits at the start, every 5 kilometers, at the halfway point and, most importantly, marked the finish.