If 2020 was the year Zoom rode the pandemic to skyrocketing success, 2021 could be the year the videoconferencing company comes back down to Earth.

Zoom started trading on the stock market in April 2019. At the time, it was known for being a rarity: a newly public tech company that actually turned a profit. One year later, the world was in lockdown for the coronavirus pandemic, and Zoom went from being a niche business software popular among tech companies to the way people did just about everything.

Not only did that mean a sharp rise in Zoom meetings for the millions newly working from home, but also Zoom birthdays and baby showers for everyone else. For many, it became an indispensable lifeline to the outside world, with a free option that limited calls to 40 minutes and an unlimited paid option that enabled people to do many of the things they used to do in person. As people joked at the time: Having a corporate Zoom account was the new having a car.

It was one of several videoconferencing options already out there, but it captured the public imagination and market share more than most. Zoom became a verb. The reason? It just worked.

Zoom has grown years in just months. At this time last year, Zoom had on average 10 million daily meeting participants. It now has 350 million. Zoom was the most-downloaded iPhone and iPad app of the year, beating perennial favorites like Instagram and YouTube. The company’s revenue is four times what it was in 2019.

Now, as we close in on two years since Zoom’s public debut, numerous headwinds make the company’s future less certain. Giant software companies like Microsoft, Cisco, and Google have mostly caught up on video chat technology, offering vastly better products than they did before Zoom entered the scene. What’s more, businesses that are cutting costs during a recession are less amenable to additional spending on software when they can lean on the contracts they already have. Microsoft Teams, which has a Zoom-like videoconferencing feature, is essentially free for companies paying for Microsoft’s Office suite. Slack, another best-of-breed workplace app that was acquired by Salesforce this week, also comes with a video component.

Perhaps most pressing, with multiple viable coronavirus vaccines likely to start distribution, we might not need to video chat so much next year. Zoom’s stock dropped nearly 20 percent in November after the news that Pfizer’s vaccine was highly effective in late-stage trials. It’s still up nearly 500 percent from this time last year, and Zoom has more than quadrupled sales year over year.

Zoom, for its part, says it welcomes a vaccine, despite the stock dips.

“Hopefully we provide a good enough service — and it’s my true intention that we provide a good enough service — that people want to use us, calamity or not,” Aparna Bawa, Zoom’s chief operating officer, told Recode.

Just nine years ago, disaffected Webex engineer Eric Yuan left Cisco to found Zoom. Now, Zoom is not only more popular than Webex, a videoconferencing service that’s been around since the 1990s, Zoom appears more popular than all of its competitors. But that enthusiasm among users hasn’t translated to sales at the same scale.

US traffic to Zoom’s website is nearly 30 times what it was in the beginning of the year, according to data from online analytics firm SimilarWeb. In October, monthly visits to Zoom were three times higher than visits to Google’s Meet and Hangouts combined, according to the firm, which can’t track web visits to Microsoft Teams because it doesn’t have its own domain distinct from microsoft.com.

Zoom had double the number of app downloads in October as Google Hangouts, and four times as many as Microsoft Teams or Google Meet. But Zoom downloads have slowed from highs earlier in the pandemic.

“Customers are still using the platform, you’re just not seeing the volume of new customers coming on as it was in the past six months,” Charlie Rogers, a software research analyst at 7Park Data, told Recode. “A lot of customers who would buy Zoom have already got it.”

In other words, Zoom might be nearing market saturation because so many people already have an account.

And being popular with the masses doesn’t necessarily lead to more income, especially since Zoom has a popular free tier with a 40-minute call limit as well as free unlimited usage for K-12 students. Corporate users are more likely to have the paid version — and they’re less likely to turn off their service, when, say, a vaccine makes it possible to meet people in person.

Finnbarr Webster/Getty Images

Zoom’s largest revenue segment — 62 percent — comes from companies with more than 10 employees, but customers with 10 or fewer employees are growing much faster, making up 38 percent of the company’s revenue, up from 20 percent at the end of last year. That segment of customers has grown as more individuals have adopted the paid service, but it’s also a more volatile segment because smaller customers can switch to a service offered by one of Zoom’s competitors more easily.

Last quarter, 18 percent of total revenue came from customers spending $100,000 or more, down from 33 percent at the end of last year.

“The real jewel isn’t about consumer or SMBs [small and medium-sized businesses], the real gold is to win enterprise,” Ryan Koontz, senior research analyst at Rosenblatt Securities, told Recode. That’s because each contract means numerous paid licenses within an organization as well as longer-term subscriptions. As Koontz put it, for enterprises, “The cost of change is very high.”

Put differently, Zoom competitors with an existing enterprise customer base have an advantage because those customers are more likely to stick with the same provider.

About half of companies surveyed by Enterprise Technology Research (ETR) have Zoom while 75 percent currently have Teams (many companies pay for multiple software subscriptions). Thirty percent have Cisco’s Webex, after a recent decline.

These numbers are still up for both products since the pandemic began. And when narrowing the data to bigger Fortune 500 companies, the market share for Teams and Webex rose this quarter, while Zoom’s declined.

Additionally, many companies that have Zoom are spending less on it. Microsoft Teams is the main reason company chief information officers cited for leaving or spending less with Zoom, according to ETR. (A number of CIOs cited security as another reason for leaving the service.) Many of those companies already pay for Microsoft’s Office 365, which has business staples like Excel and Word. Included in the cost of the software suite is access to Microsoft Teams and its videoconferencing features, making Teams a no-brainer for companies trying to cut costs.

This is an argument Zoom is used to.

“When Eric [Yuan] founded this company, videoconferencing was then thought of as a saturated market. There were lots of very large legacy providers including Microsoft that continued to bundle different services,” Bawa said. “And Zoom still has done pretty darn well.”

Zoom still has plenty of enterprise users, and it’s also popular among small businesses. While this smaller, fast-growing segment isn’t as profitable as big companies, these customers are still important for Zoom’s future.

“Don’t underestimate the number of small and medium-sized businesses,” Wayne Kurtzman, research director of social and collaboration at market research firm IDC, said. “The market has room for multiple leaders.”

While Zoom earned popularity because of its dependability and ease of use, its competitors have gotten a lot better in these respects by simplifying their services and bulking up the quality of their video calls. Now, the baseline service that Zoom and its competitors offer is pretty similar. They all have videoconferences that are pretty easy to join, work pretty well, and are pretty secure. So all these companies are currently fighting to differentiate themselves with new and better products.

This year, Zoom had to fix security concerns to bring its service more in line with its competitors. A series of high-profile security mishaps — including Zoombombing, a vulnerability that let websites hijack Mac cameras, and Zoom routing calls through China — eventually led Zoom to bulk up its security. In addition to fixing the issues that led to the mishaps, Zoom hired former Facebook security executive Alex Stamos as an outside consultant and began offering end-to-end encryption in October.

“Zoom is catching up at a really quick rate to those like Teams and Webex,” Frank Dickson, program vice president within IDC’s cybersecurity products research practice, told Recode.

Bawa said Zoom’s enterprise customers are a testament to the bolstered security.

“The validation is that we have a significant number of our large enterprise customers that go through multiple rounds of security review in financial services, in the government sector, defense — you name it — retail, etc.,” Bawa said. “And we have passed them and continue flourishing in those accounts, expanding our footprint.”

So now, the competitive battleground for videoconferencing software is all about new features. Both Microsoft Teams and Cisco’s Webex have added at least 100 new features since the pandemic. They’ve added noise cancellation software to deal with the sounds of working from home: babies crying, dogs barking, neighbors mowing their lawns. They also started offering live transcription. Microsoft introduced Together Mode, which places conference attendees against a shared digital background to give them the feeling of being in the same room. To accommodate its governmental customers, Webex even added a new feature that allows legislators to emulate voting on laws.

“A direct outcome of the pandemic was, hey, our innovation velocity has to increase because this has become a far more strategic technology today than it was five years ago,” Jeetu Patel, senior vice president of security and apps at Webex, told Recode.

Meanwhile, Facebook realized early in the pandemic that people were using its Portal video chat service more for group events than one-on-one conversations, so it made that easier with link sharing and call scheduling.

All of the platforms have enabled fun backgrounds and Snapchat-like augmented reality filters.

In addition to many of the same features as its competitors, Zoom has been rolling out new potential revenue streams. After launching Zoom Rooms and Zoom Phone last year, Zoom announced more new products in October: OnZoom, a video events platform that will allow people to sell tickets, and Zoom Apps, which lets people navigate to other workplace apps like Dropbox and Slack within Zoom. Zoom sees these new products as commonsense additions to its core tool, which it says could still get better.

But taken together, all of these moves could be a sign of weakness.

“Anytime an enterprise tech company that’s a one-trick pony announces new products, it’s because the current product is maxed out,” said market researcher Thomas DelVecchio.

The end of the pandemic does not signify the end of video calls. It will certainly mean less video usage, but video will likely forevermore be a component of meetings, if not a dire necessity.

After the pandemic, the vast majority of office employers plan to use a hybrid work model, wherein some of their workforce works remotely at least some of the time. As large as it was this year — $7.9 billion — the videoconferencing market is expected to grow next year to an estimated $9.7 billion with 90 percent of North American businesses likely to spend more on it, according to IDC.