Quaid Walker, chief executive of Bezel, an online marketplace for pre-owned luxury watches, was in a celebratory mood. “We announced a billion dollars in listings today,” he said on a video call last month from Los Angeles.

For the 31-year-old, the milestone was personal. In 2019, while he was working at Google, he began searching for a pre-owned Rolex Submariner model nicknamed Hulk.

After months of research, Mr. Walker eschewed the industry’s two oldest and largest resale platforms, Chrono24 and eBay, and bought the watch from a dealer an acquaintance had used. But he could not stop ruminating on the complicated experience.

“It felt so cumbersome and challenging to buy this thing,” he said. “My thinking was, ‘I don’t get nervous when I spend thousands of dollars on sneakers on the GOAT and StockX apps. Why is this so concerning for watches?’”

Mr. Walker was not the only tech-savvy watch enthusiast intrigued by the seemingly risky business of buying a secondhand timepiece. Since 2021, when Bezel was founded, a flurry of start-ups have set up shop, intent on solving the two biggest challenges in the market: a lack of pricing transparency and concerns about authenticity.