Vanja Josifovski has left Pinterest to join travel and accommodations company Airbnb, where he will be CTO of Airbnb Homes, the company’s largest and most mature business unit, VentureBeat has learned.

Josifovski, who was at Pinterest for four years, most recently as CTO, oversaw the company’s overall technical vision and strategy, including the building of its machine learning and search platforms, as well as managing some of the company’s core engineering teams.

Airbnb hired Josifovski “to bring together homes engineering, artificial intelligence, machine learning and data science under a single leader,” Airbnb Homes president Greg Greeley said in a statement.

It’s the second poaching of a high-level exec by Airbnb in five months. In October, Airbnb nabbed Aristotle Balogh from Google, where he was VP of engineering, to become CTO of Airbnb’s overall platform.

High-profile defections to rival tech teams within Silicon Valley are still relatively rare, even as furious poaching efforts happen all the time at the lower rungs of engineering. Most large companies manage to keep their executive talent locked up, with lavish pay and other perks. When it comes to hiring AI talent, companies have had easier pickings by poaching university researchers, where much of the pathbreaking AI work has been done until now.

So when such moves do happen — for example, when Apple last year snagged Google’s John Giannandrea, who led search and artificial intelligence at the search giant — they draw attention.

While Pinterest and Airbnb are smaller than Google or Apple, they are both fast-growing, respected tech companies that are about to go public — as early as this summer. And they’re hiring rapidly. However, Airbnb was valued at more than $30 billion last year, or close to double the value of Pinterest. Airbnb also has a larger team, at more than 5,000 employees, compared to about half that for Pinterest. And Pinterest has recently been hiring more on its business side than on the technical side.

“It’s an amazing company,” Josifovski said in a call with VentureBeat, about Airbnb. “It’s a company that I feel has a shot at changing the world in a good way. It’s also a company that is very ambitious. The opportunities are just endless, of what Airbnb can do, in travel and well beyond travel, actually.”

Airbnb now has two CTOs. Balogh will lead the technical aspects of Airbnb’s platform overall, while Josifovski will lead all areas of technology strategy for the Homes business — which has its own sizable engineering team. Josifovski will report to Greeley.

“Vanja will spearhead development of our technical vision and direction of our platform capabilities across our Homes business,” Greeley said in an email statement to VentureBeat.

VentureBeat learned of the move because Josifovski is slated to speak at our Transform event in July, and he gave us a courtesy heads up — given that we are planning the event’s agenda. He’ll still be speaking at that event, which is about how companies are using AI to transform their businesses. He also spoke at our event last year (see video above; article here) in his trademark thoughtful and clear style.

“There isn’t a part of the company where we don’t use AI,” he said of Pinterest, during last year’s talk. And more generally, he said: “AI is going to be available in everybody’s palm. … You can be a small shop owner and be able to use it. You can go online and pick it up. … The democratization of AI is a bigger factor in driving anything.”

Airbnb offers an interesting technical challenge, Josifovski told VentureBeat, which is to build architecture for scaling its multiple business lines. Moreover, after spending most of his career in companies that draw most of their revenue from advertising, he said he is personally interested in trying something not advertising based.

Pinterest has made a string of announcements lately, from personalized shopping to updating its Shop the Look feature. Lens Your Look, which lets you take a picture of an item of clothing and find similar options, was introduced in 2017. The company’s centralized ML platform supported most of those applications, and as such Josifovski’s hand was behind most of those announcements.

“Vanja made important contributions to Pinterest, and we wish him well,” a Pinterest spokesperson said. “We’re grateful for his work in scaling our engineering team with strong technical leaders who oversee areas like computer vision and machine learning, and continue to build the organization as it grows.”

Prior to becoming CTO in 2017, Josifovski led Pinterest’s growth engineering team during the company’s international expansion. He was also responsible for Pinterest’s Discovery team, which included personalization and computer vision. He headed up the Pinterest ads engineering team when Pinterest was building out its ad-driven business model and rapidly expanding revenue growth.

Josifovski has penned over 100 papers and holds more than 30 patents. Prior to Pinterest, he spent most of his career in research labs, including at Google AI, Yahoo Research, and IBM Research.

Josifovski is the latest in a string of hires by Airbnb to the Homes business. Others include Laura Chambers, general manager for Homes hosts and community; Vinayak Hegde, who leads all growth marketing activities for Homes; and Romain Voog, head of worldwide operations, sales, and geographies.