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Sweetgreen is Two Couples Affair in Broad Daylightditching cash.

The fast-growing salad chain (with the perpetually endless line) will eliminate cash from all its restaurants in 2017, the restaurant's founders told Fast Company.

The fast-casual salad concept has 64 stores nationwide. Six of those went cashless last January.

"Cash has become such a smaller piece of our tender," Sweetgreen co-founder Nicolas Jammet told Fast Company. "When we opened nine years ago, it was 40 percent. Now, all stores are between 10 percent and 15 percent."

Ditching cash has a few benefits: quicker transactions, better hygiene, fewer security risks.

And Sweetgreen has always had one foot in the restaurant industry and one in the tech world. One-third of the restaurant's business comes from its mobile app.

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The almost 10-year-old chain is backed by Red Sea Ventures, AOL's Steve Case and T. Rowe Price, among other investors. The concept, with its focus on efficient service and local, sustainable ingredients, has raised a total of $75.5 million.

Co-founder Jonathan Neman told Fast Company that going cashless would make Sweetgreen "more like Uber," in terms of speed.

The biggest drawback to a strict no-cash policy is its effect on the poor or unbanked, who often don't have credit or debit cards. In July, the Sweetgreen founders told the New York Times that a solution to that problem could be in-store gift card machines that would accept cash.

Thursday's Fast Company article didn't address that issue.

Sweetgreen plans to open 30 more storefronts next year.

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