Airtable has raised $52 million in Series B funding led by Caffeinated Capital and CRV.

Airtable is an app that creates spreadsheets, like Google Sheets and Microsoft Excel. But the cells can fit much more than just numbers, including photos and lists.

Airtable has become a sleeper hit in Silicon Valley, earning love from users and companies like Tesla, WeWork, Airbnb, and Time magazine.

An initial public offering is the plan — Liu sold his last company to Salesforce and doesn't want to go that route again.

Airtable, a spreadsheet app that has become one of Silicon Valley's sleeper hits, has raised $52 million in new funding in a round led by Caffeinated Capital and CRV to bring its total to $62.6 million.

When it was founded in 2012, Airtable was a small, business-focused spreadsheet program. It has since found new audiences, as companies like Tesla, Airbnb, and WeWork — as well as smaller teams and individual users — have come to rely on Airtable to organize their data.

The secret to Airtable's success, according to its CEO, Howie Liu, is that it makes it easy to make a custom app. Every cell of an Airtable spreadsheet can store anything, including photos and lists. Adding an interface on top can turn it into a simple but powerful app — without coding.

"We think we can be what Windows was for personal computing," he said. "We're confident we can be the Apple or Microsoft of the low-end-app space."

For example, Tesla uses Airtable to store information and keep track of every car that leaves its factory in Fremont, California. The video and photo teams at Time magazine and Fortune use Airtable to manage their entire production schedule too.

"It really allows people with little or no technical knowledge to build high-level workflow systems," Liu said.

Airtable lets you build basic apps without coding. Airtable

The state of Airtable's business

Liu's first company, Etacts, was acquired by Salesforce in 2010, when he was 21. A year later, after realizing how limiting Google Sheets and Microsoft Excel were, Liu quit to start Airtable.

Ashton Kutcher, who had invested in Liu's first company, also invested in Airtable after Liu pitched him in his trailer on the set of the show "Two and a Half Men."

It worked out, and Airtable is growing fast. Though Liu didn't disclose specifics, he said revenue was up 500% from the year-ago period.

The app has millions of users and "thousands" of sign-ups every day, Liu says.

Liu said all the interest caught him a little by surprise.

"If you asked me on the day we launched if a few years later we would be signing six-figure enterprise clients, I would have said no," he said.

Airtable's mapping block. Airtable

Liu also says he's had good advice along the way.

Bill Macaitis, the former chief marketing officer of Slack, is an adviser to Airtable, as is Amanda Kleha, formerly the head of marketing at Zendesk — both help assist with Airtable's enterprise-marketing push. Dylan Smith, the CFO of Box who's a college friend of Liu's, has also acted as an adviser.

Airtable isn't yet profitable, Liu says, but could be "cash flow positive at a moment's notice." And an initial public offering is the goal; Liu doesn't want to sell his company again.

Liu said the funding would go toward hiring, product development, and opening an office in New York.

Airtable is also launching a new product called Blocks, designed to allow users to build more-involved apps for businesses — but still without coding. For example, a mapping block could let a film studio track its shoots around the globe in real time, including the status of equipment rentals and the production itself.

Liu attributes Airtable's growth to a change in marketing strategy. Recently, he and his team shifted their focus to going after larger enterprise customers rather than smaller businesses and startups. Once they made that decision — and started blanketing San Francisco in billboards — word began to spread.

"It's crazy how Airtable kind of blew up," Patrick Perini, the vice president of product at Mira, another startup based in San Francisco, told Business Insider.

Perini says he's considering moving all of Mira's operations to Airtable.

"All of my developer friends are pretty excited about it," Perini said.