While many popular megacap tech companies have already reported earnings, some smaller companies will get the spotlight this week. Two fast-growing mid-cap tech stocks worth watching today and tomorrow are cloud-based contact center specialist Five9 (NASDAQ:FIVN) and website-building platform Wix.com (NASDAQ:WIX).

Both stocks could see big moves when they report their latest quarterly results. Five9 reports its fourth-quarter results after market close today and Wix will release its quarterly update before the market opens on Thursday.

Ahead of these two companies' earnings releases, here's a preview of some key areas to watch.

A chart showing two stock prices rising as trading volume spikes

Image source: Getty Images.

Five9

Shares of Five9 have surged this year, rising 17% so far. The sharp gain in the stock price puts pressure on the tech company's fourth-quarter update today.

Five9 investors will want to check on the company's top-line momentum. Total revenue during Q3 was $83.8 million, up 28% year over year -- an acceleration from 27% growth in Q2. Rapid growth has been fueled by large organizations, or the company's "enterprise subscription revenue." Trailing-12-month enterprise subscription revenue for the period ending Sept. 30 was up 36% year over year.

For Five9's fourth quarter of 2019, management said it expected revenue between $86 million and $87 million, up about 20% from revenue of $72.3 million in the fourth quarter of 2018. Analysts, on average, expect Five9 to report revenue of $86.7 million. 

Wix.com

Investors are similarly excited about Wix stock recently. Shares are up 24% year to date. Also like Five9, Wix's business is growing rapidly. In Q3, revenue was up 26% year over year. Though this was a slight deceleration from 27% growth in Q2. Investors, therefore, should look to see if revenue growth decelerates further in Q4. Management guided for revenue during the period to rise 24% to 25% year over year to between $204 million and $206 million. Analysts, on average, expect Wix's fourth-quarter revenue to come in at $205.5 million.

Beyond revenue growth, investors will want to see if Wix can continue growing its user base rapidly. The company added 114,000 net premium subscriptions and 5.5 million registered users during Q3. This brought total premium subscriptions and registered users to 4.4 million and 160 million, respectively. In Q3, premium subscriptions were up 15% year over year and registered users grew 17% over this same time frame. Investors should look for Wix to post similar year-over-year growth rates for these metrics in Q4.

Wix is scheduled to report its fourth-quarter results before the market opens on Feb. 20.