Share of edge-computing company Fastly (FSLY 0.14%) have been pummeled recently. The stock has nosedived from highs above $130 earlier this month to about $75 more recently. That's a whopping 42% decline. Earlier this month, investors went into panic mode when the company said it would miss its third-quarter revenue guidance.

With such a huge pullback for the growth stock recently, investors will be watching Fastly's third-quarter earnings report this week closely. The tech company is slated to report its third-quarter results on Wednesday.

Here are some key metrics investors should check on when Fastly's third-quarter results go live.

A computerized-looking drawing of a cloud.

Image source: Getty Images.

New customer additions

In Fastly's second quarter, the company saw its largest increase in net new customers in its history. The edge-computing specialist's total customer count increased from 1,837 in the first quarter of 2020 to 1,951. Enterprise customers, or those who spend $100,000 or more on Fastly's platform over a trailing-12-month period, increased from 297 to 304 over the same time period.

Investors should look for customer growth to be just as strong in Q3. Given how early Fastly is in its growth story, any slowdown in customer growth could be a cause for concern.

Net retention rate

Since it went public in 2019, Fastly has maintained impressive net retention rates (the change in monthly revenue from existing customers in the last month of a given period compared to the last month of the same period in the year-ago period).

The company's net retention rate in Q2 was 138%, though this was abnormally high due to increased usage during the peak of stay-at-home orders. In Q3, Fastly's net retention rate will likely fall back to levels closer to what was seen before Q2, such as the 130% rate Fastly achieved in Q1.

Revenue guidance

Finally, investors will look to see what management guides for full-year revenue. When Fastly reported preliminary third-quarter revenue below expectations, management withdrew its outlook for the full year. But Fastly CEO Joshua Bixby did say that that demand for its platform remains strong. In addition, Bixby confirmed that the company would discuss its outlook when it reports third-quarter results.

Management's lowered view for Q3 still notably translates to rapid growth. The company said revenue during the period will be between $70 million to $71 million, representing 42% year-over-year growth. But investors should expect a deceleration in Q4, as the stay-a-home trends that catalyzed increased internet usage (and in turn revenue growth) in early Q3 may not be as prominent in Q4.

Previously, management was guiding for full-year revenue to be between $290 million and $300 million. Given the company's worse-than-expected revenue performance in Q3, it wouldn't be surprising to see management lower that outlook to a forecast for revenue between $280 million and $290 million.

Fastly is scheduled to report its third-quarter results after market close on Wednesday, Oct. 28.