Two real estate startups are joining forces to take on online apartment rental industry giants Zillow, Trulia, and Craigslist.

Zumper, which connects brokers and owners with potential renters, is acquiring apartment listings startup PadMapper. The deal was under $10 million in cash and stock.

Zumper, which has raised $20 million in funding from Kleiner Perkins and Goodwater Capital, had 4 million monthly visits to its site in January, up from 50,000 visits two years ago. The company says it’s on track to bring in $5 million in revenue in 2016, and is aiming to be profitable by September.

Whether a combined Zumper and PadMapper can take on the likes of Craigslist and others is a formidable challenge. Zillow has hundreds of millions of monthly visitors, and Craigslist counts 50 billion page views per month.

PadMapper aggregates rental listings from the web from sites like Airbnb onto a map so that users can find homes and apartments for rent by location, in New York, San Francisco and other cities. Craigslist successfully sued PadMapper for including Craigslist’s rental listings on its service. PadMapper ended up having to stop including the listings in its searches.

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Zumper makes money by advertising and allowing renters to advertise their listings more prominently on the site.

With the two services combining, Zumper and PadMapper expect to grow to 8 million to 10 million unique visits per month by June. “We want to make finding your next apartment as easy as booking a hotel,” said Anthemos Georgiades, the CEO of Zumper.

Part of what distinguishes Zumper from Zillow and Craigslist is that users can submit rental applications through the site, instead of having to fill out paperwork by hand. The vision, explained Georgiades, is that the company will take renters through the entire process, from searching to applying, and then closing their leases for an apartment or home. Already, Zumper has thousands of renters using the site’s application tool each week.