SAN FRANCISCO • Silicon Valley goes through its own unique shoe crazes. There were Vibrams. There were Crocs.
Now comes the Allbirds, a knit wool loafer. In uncomfortable times, Silicon Valley has turned to a comfortable shoe. If there is a venture capitalist nearby, there is probably a pair of Allbirds too.
Google co-founder Larry Page wears Allbirds, according to the shoemaker, as do former Twitter chief Dick Costolo and venture capitalists Ben Horowitz and Mary Meeker.
Founded by a New Zealand soccer star and a clean-technology entrepreneur, Allbirds makes the sneaker-like shoes from wool and castor bean oil.
Slightly fuzzy to the touch, Allbirds have minimal styling (tiny logos only) and come in two versions: a runner and a lounger. Both styles, for men and women, sell for US$95 (S$130). Next month, Allbirds is opening its first store in Manhattan.
In true Silicon Valley fashion, Allbirds is a start-up. Is it venture funded? Of course it is. The company has raised US$9.95 million over the last year to spread its vision. But this being start-up land, a shoe is never just a shoe.
"We're about the distillation of solutions, the refinement and crafting of forms in a maniacal way," said Mr Tim Brown, the Allbirds co-founder from New Zealand.
Silicon Valley likes a uniform. Standing out with a personal style in tech is generally shunned, since it implies time spent on aesthetic pleasures rather than on work. Tech leaders often adhere to strict personal dress codes (such as Facebook founder Mark Zuckerberg's grey T-shirt) and young entrepreneurs study the social media cues of the venture capital class, who tend to select investments in part based on who looks like them.
So, for now, this insular world has settled on Allbirds.
At a gathering last month hosted by the venture capital firm August Capital on Sand Hill Road in Menlo Park, California, about 1,000 entrepreneurs and investors mingled on a concrete patio over margaritas and devilled eggs to celebrate summer.
Guests wore other shoes - New Balance, Top-Siders, Tevas and a rare dress shoe were spotted - but the furry-looking Allbirds was, by far, the most common.
Mr Serik Kaldykulov, managing partner for Elefund, which finances early-stage start-ups, wore a pair as he waited to get into the party.
"Everyone's wearing them. Sometimes, it is awkward, especially if we're wearing the same colour - but then, it's an icebreaker," said Mr Kaldykulov, who owns four pairs in different colours.
"Anything with laces becomes less efficient," said Mr John Kim, chief executive of SendBird, a start-up that helps software engineers build chat features within their apps. He sported a pair of light grey Allbirds.
He said he wore Allbirds for "all reasons and purposes" - except to a recent barbecue, for fear that sauce could seep in. Allbirds, which are machine washable, are meant to be worn without socks. (Some have complained about how quickly the shoes wear out, though Allbirds has said in a statement that the latest line is more durable than earlier iterations.)
Yet today's hot shoe may easily become tomorrow's Google Glass in a drawer. So what to do except strike before the moment slips away?
Mr Joey Zwillinger, an Allbirds co-founder and former clean-tech entrepreneur, said the company planned to raise more money. "We have pretty big aspirations," he said.
At Allbirds' office, in one of San Francisco's oldest buildings on a high-end shopping street downtown, he and Mr Brown, both 36, told the story of how they became Silicon Valley's cobblers.
In 2009, Mr Brown, then vice-captain of the New Zealand soccer team, was trying to figure out his next chapter. He liked design and, before attending business school, made simple leather shoes for his friends. But the shoes were uncomfortable.
"Coming from a land of 29 million sheep, wool was obvious," he said. With a research grant from New Zealand's wool industry, he began a Kickstarter campaign to make wool shoes in 2014. Within four days, he had sold US$120,000 worth of shoes through the crowdfunding website. He shut down the campaign in a panic. "I didn't understand how it could be made."
Mr Zwillinger, an engineer in biotechnology, was working in Silicon Valley and struggling to sell algae oil as a replacement for petroleum. (It was too expensive to catch on.) Their wives, who are best friends and former Dartmouth roommates, introduced the two men. Mr Brown travelled to Northern California to meet Mr Zwillinger and get advice on supply chains. Mr Zwillinger cooked a lamb stew and the two decided to form a business.
"One of the worst offenders of the environment from a consumer product standpoint is shoes," Mr Zwillinger said. "It's not the making; it's the materials."
Allbirds are made of a very fine merino wool, each strand 17.5 microns wide. "Which is 20 per cent of the width of the average human hair," he said.
The shoe's name comes from what explorers supposedly first said of New Zealand: "It's all birds." Also, Mr Zwillinger is an avid birder.
For a while, there was little tech interest. Then, in the middle of last year, Mr Zwillinger noticed tech leaders posting about the shoes on Snapchat and Twitter. "All of a sudden, men's size 12 and 13 went out of stock," he said. "Our demo went from mostly female to way male. A run started happening."
Today, the two men have 50 employees in their San Francisco headquarters, 350 contractors in a factory in South Korea and 40 at a warehouse in Nashville, Tennessee. The Brooklyn-based Red Antler consultant firm worked with them on branding and design.
Mr Dave Morin, an investor at Slow Ventures, which put money into Allbirds, said the start-up was a place to invest "in the material science and the dream".
"No. 1, breakthrough material; two, you didn't need socks, that changes the idea of shoes; and No. 3, it was a single shoe," he said. "I think of it as classic Apple simplicity strategy."
Others were more hesitant.
"I don't think Silicon Valley has ever set, is currently setting, or ever will set any fashion trends," said Mr Costolo, the former Twitter chief executive who wears Allbirds.
Mr Brown and Mr Zwillinger said they planned to release new colours of shoes (currently six are available, including pine and moss) and, eventually, shoes for children. A reporter saw a pair of flip-flops that appeared to be made of bamboo or very firmly packed leaves. "Market research," Mr Zwillinger said.
The co-founders are hoping to appeal to the same consumer who buys basic clothes from Everlane, also based in San Francisco, and eyewear from Warby Parker. (Two Warby Parker founders are Allbirds investors.)
Shoes are an US$80 billion industry in the United States, where the average American buys eight pairs a year, according to a Euromonitor International Passport report.
"If you were going to design one sneaker and only one, what would it look like? We focused on this idea of a singular solution," Mr Brown said. "The right amount of nothing."