The initial public offering (IPO) market over the past two years has seen numerous high-growth tech companies become available for public investment. Demand has driven some runaway valuations and may have kept investors on the sidelines. But recent pullbacks in cloud stocks may be providing an opportunity for those with a long-term mindset.

If you're looking for some newly public tech companies to add to your watch list, Slack Technologies (NYSE:WORK), Zscaler Inc (NASDAQ:ZS), and Zoom Video Communications Inc (NASDAQ:ZM) should be in consideration. 

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A trio of fast-growing software services

First, here are some quick stats on all three companies.

Company

IPO Date

Trailing-12-Month Revenue

Most-Recent-Quarter Revenue Growth

Price-to-Sales Ratio

Dollar-based retention rate

Slack

June 20, 2019*

$507 million

58%

22

136%

Zscaler

March 16, 2018

$302 million

53%

18

118%

Zoom

April 18, 2019

$463 million

96%

41

130%

Source: Company news and financial releases. Table by the author. *Note: Slack released its stock under a direct public offering (DPO). 

Slack is the youngest as a public company and boasts the highest trailing-12-month revenue. Zoom has the highest price-to-sales ratio, which points to it being the most "expensive," but it also carries the most impressive revenue growth. Zscaler seems the best value, but also has the lowest most recent quarterly growth number. All three have impressive dollar-based retention rates. 

Let's dive into why each should be on your watch list.

1. Slack: The communication upstart takes on an industry behemoth

Slack Technologies has come a long way since the Searchable Log of All Conversation and Knowledge (or Slack for short) was created as an internal tool to help game developers collaborate better. Today, over 100,000 companies pay to use Slack's software, and 12 million daily active users spend about 90 minutes a day using it to collaborate with colleagues.

It's gaining momentum with over 600,000 developers who've built over 500,000 applications that integrate with the platform. These stats fuel a projected top-line growth of over 50% for the full year. But the stock is being dragged down due to fears of competition from Microsoft's Teams application that's bundled with Office 365.

The CEO isn't worried about big Mr. Softy and notes that 70% of its top 50 customers use Slack to integrate with Office 365. Grabbing a niche market from a deep-pocketed well-established giant is risky, but some believe this stock could be a winner for long-term focused shareholders. It may be worth it for you to get to know this company a little better.

2. Zscaler: Security for the new cloud landscape

Securing your business network is getting harder than ever. Employees have expectations of getting access to the network from any device and from anywhere. Applications are moving outside of a company's on-premise data centers into the cloud, and even equipment is now becoming "smart" and connecting wirelessly to the internet.

The days of putting up firewalls around your data center are no longer sufficient. Enter Zscaler, which was born as a cloud-based security service and isn't dependent on physical constraints to protect your data. 

Keyboard with enter key changed to the word cloud with an image of data going in and out of the fluffy cloud.

These recent IPO cloud companies are only just getting started. Image source: Getty Images

Zscaler converts what was once a number of hardware appliances in the data center and replicates the functions in the company's software cloud. As a customer converts over to security in the cloud, it can simplify its network architecture and scale without having to add hardware.

This model has been hugely successful and has driven grown at a 50%-plus annual growth rate for the last three years. The market has punished the stock recently because of its lower-than-expected 30% to 34% revenue growth projection for the upcoming fiscal year.

Management pointed to longer sales cycles with larger companies as being the primary reason for weaker projection. But landing larger customers bodes well for the long term for this cloud-based security service and is a reason to add this beaten-down software-as-a-service (SaaS) play to your watch list.

3. Zoom: Meetings don't have to suck

With a lofty goal of making "Zoom meetings better than in-person meetings," Zoom Video Communications has a focus on utilizing technology to improve communications and bring happiness into the workplace. Attending a meeting from any device from anywhere is only the beginning. 

Features like live transcripts, automated people count, virtual backgrounds, polling, chat, and tracking meeting action items are just a few of the things that make this a superior platform for the modern-day workplace. Integration with other software tools such as Microsoft Office 365, Slack, and Salesforce.com help make getting started and ongoing interactions easier. Over 90% of customers report increases in performance and engagement after adopting the software for their workplaces.

The platform is seeing tremendous adoption across companies large and small, powering impressive revenue growth that more than doubled for each of the last four quarters. But it's still the early days for this company. With an estimated 200 million businesses globally, Zoom is only used in less than 0.5% of them.

Investors who want to learn more can tune in to the next earnings call, which, of course, is hosted via streaming video on Zoom's software.