Zoom Video Communications Inc.'s explosive growth is beginning to slow down as the pandemic drags on, but analysts expect new software offerings — particularly its cloud-based phone service — will continue to drive revenue into the second half of the year.

The company's fiscal fourth quarter revenue of $882.5 million was more than four times its year-ago top-line figure, but roughly a year into the COVID-19 pandemic, comparisons were expected to get tougher. The company surprised to the upside with its fiscal 2022 revenue guidance of between $3.76 billion and $3.78 billion, compared to then-consensus expectations of about $3.53 billion.

Looking at quarterly expectations, Zoom is guiding for revenue growth of about 175% for its fiscal first quarter, the first time it will have a year-ago comparison against pandemic-fueled gains. Analysts expect growth rates to fall to double-digit percentages from there, as quarterly revenue begins to flatten out above $950 million in Zoom's fiscal third quarter, which ends in October.

For its full-year fiscal 2021, which ended in January, Zoom reported revenue of $2.65 billion, compared to $622.7 million in fiscal 2020.

Despite the upside surprise, Bernstein analyst Zane Chrane called Zoom's fiscal 2022 revenue guidance conservative and said he continues to anticipate the company will rake in $4 billion in revenue over the course of the year.

"To reach $4 billion, the company would have to add less than half the average incremental revenue each quarter as what they added this Q4, a seemingly attainable hurdle," Chrane wrote in an analyst note. He reiterated his "outperform" rating and $610 price target on the company's stock. "We continue to expect positive surprises attributable to strong renewal rates, share gains from legacy vendors, and triple digit growth in Zoom Phone," the analyst said.

D.A. Davidson & Co. analyst Rishi Jaluria said Zoom's forecast showed that its growth is sustainable post-pandemic, especially as it expands to other areas of business collaboration and communication.

"While FY21 was an unprecedented year, investors were worried the benefits were temporary or one-time in nature and that Zoom had effectively pulled forward its entire total addressable market," Jaluria wrote in an analyst note. "The outlook, in our view, dismisses this worry and highlights how critical Zoom is in enabling the hybrid future of work."

Jaluria maintained his "buy" rating and $600 price target on Zoom's stock, saying that the company's expansion to other areas within business collaboration and communication will result in a long runway of growth even with existing Zoom customers. He highlighted the recent growth of Zoom Phone as an example of how the company has an opportunity to continue expanding into a "true multi-product platform."

Zoom Phone ended fiscal 2021 with about 10,700 customers with more than 10 employees, up 269% year over year.

"This suggests that only 2.3% of Zoom's 467,100 customers with more than 10 employees have Zoom Phone, suggesting ample runway ahead to further penetrate its base," wrote FBN Securities analyst Shebly Seyrafi in an analyst note. He reiterated his "outperform" rating and $525 price target on Zoom's stock.

Raul Castanon, a senior research analyst covering workforce collaboration and communication platforms at S&P Global Market Intelligence's 451 Research unit, said Zoom Phone is well timed, launched just as companies started accelerating plans to upgrade their voice services.

"Zoom is in a very good condition to make a significant impact in this space as they already have an established base with their video conference product and can easily offer Zoom Phone to those customers," Castanon said.

Companies are increasingly favoring vendors that offer multiple products that cater to their needs over multiple vendors and platforms, Castanon said. That is why services from Zoom's larger competitors, such as Microsoft Corp.'s Teams and Cisco Systems Inc.'s Webex, are also expanding their unified communications as a service, or UCaaS, capabilities.

"With Zoom Phone and the rumored chat and email services, Zoom is looking to compete directly with these companies as a UCaaS platform," Castanon said.