When A$AP Mob released the video for their song "Raf," an ode to the menswear oeuvre of Raf Simons, they worked with the designer and his team to source the rare archival pieces that A$AP Rocky, Quavo, Playboi Carti, and others model in the video. But even they couldn't track down a few vintage Simons items, like an oversize hoodie from his fall 2005 collection or a parka from fall 2004. So they turned, as some menswear brands who have missing pieces in their back catalogue have done, to the team behind Grailed, the men's resale site that has become a hub for the rabid menswear community.

Lately, the site, which currently has 700,000 users, is becoming less of a secret weapon and more of a prominent name outside of its own marketplace. Fashion-focused rappers on the come up like Playboi Carti have been turning to Grailed for clothes for photo shoots—for Carti's recent stories in W and Vogue, Grailed provided the looks, and in his video for "Magnolia," he can be seen in a series of Rick Owens looks, also courtesy of Grailed. They also provided pieces to the R&B singer 6lack for a Paper story, and Grailed's Soho offices have become known to host drop-ins from the likes of Lil Uzi Vert and Luka Sabbat.

"We're not hitting these people up to get business," said Lawrence Schlossman, Grailed's brand director and founder of the now-defunct cult menswear site Four Pins. "These things are just fun for the people who work here."

Grailed was started in 2014 by Arun Gupta, now the CEO, out of a sense of frustration with the unfriendly way coveted men's fashion was being bought and resold online. (A grail is a hard-to-acquire item that tends to appreciate in value over time.) "What killed me on Styleforum was that it took three clicks to get to a photo, and then a minute to load it," Gupta, who previously founded a tech startup in San Francisco, recalled at the Grailed offices recently. "Why can't I have a full feed of photos? I was like, I can probably build that. So I did."

The site took off thanks in part to its clean Instagram-style look and ease of use, and the fact that a user's feed seemed to reflect the moods of menswear enthusiasts at any given moment. The lines that formed around the Supreme store in downtown Manhattan on a Thursday morning awaiting the weekly drop would lead to, not long thereafter, a flood of Supreme on a Grailed shopper's feed. It got to the point that the company had to create a separate vertical on the site, Hype, for those chasing the latest in Supreme or Bape or Yeezy. At this point the site offers over 40,000 Supreme items—out stocking even eBay.

Grailed established its foothold in the hypebeast resale market by getting there early—in 2014, there was nothing else that brought together a combination of eBay, men's fashion forums, and niche Facebook groups—and by reflecting the particular tastes of its niche audience (Commes des Garcons, Rick Owens, Saint Laurent are all well represented, as is newer favorites like Gosha Rubchinsky and streetwear brands like Palace and Bape). But despite recent reports that show menswear growth will outpace women's over the next few years, the company is now turning its eye on the bigger and more lucrative market: the exploding women's secondhand arena. Despite the established presence of significantly larger sites like the RealReal, ThredUp, and Tradesy, Grailed is betting that its formula will find an audience when it launches its own women's site, Heroine, in September. Unlike those other sites, which operate like digital consignment stores, Heroine is based (like Grailed) on peer-to-peer buying and selling that feels like being part of a club of like-minded enthusiasts.

"User feedback will be huge for us in the beginning," said Kristen Dempsey, Heroine's brand director. Part of the reason for the women's site was, in fact, due to demand from Grailed's existing female customer base. When it launches next month, Heroine will include some special women's fashion grails, like a vintage Comme des Garcons dress that is a design currently in the Rei Kawakubo retrospective at the Met. Still, Heroine will rely on its new users to recreate the strong point of view and sense of community of its brother site. "We get emails all the time that go, 'I met my homie on Grailed,'" Schlossman said. "And now they're shopping buddies."

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