Amazon.com (NASDAQ:AMZN) crushed analyst estimates when it reported its first-quarter results earlier this year. Earnings per share, in particular, soared past analysts' average forecast for the metric as the company benefited from improved economies of scale.

The stellar quarter means investors will be watching Amazon closely next week when the e-commerce and cloud-computing giant reports its second-quarter results. The company is scheduled to post its quarterly update after market close on July 25.

Ahead of Amazon's earnings release, here's a look at three metrics worth checking on when the update goes live.

Boxes on a conveyor belt in an Amazon fulfillment center

Image source: Amazon.com.

Revenue growth

Amazon's revenue growth has been slowing recently. First-quarter revenue rose 17% year over year to $59.7 billion, coming in at the high end of management's guidance for revenue between $56 billion and $60 billion. But this is down from the 20% year-over-year revenue growth seen in Q4.

Of course, a deceleration during the quarter made sense. Q1 represented the first quarter in which Amazon's acquisition of Whole Foods is now reflected in both the current and year-ago periods. But other aspects of Amazon's business, including third-party seller services, subscription services, and Amazon Web Services, saw growth decelerate in Q1 as well.

Management guided for second-quarter revenue to be between $59.5 billion and $63.5 billion, representing 13% to 20% year-over-year growth. Analysts, on average, are expecting Q2 revenue to rise about 18% year over year.

Earnings per share

One area Amazon has really been outperforming expectations is its bottom line. First-quarter earnings per share came in at $7.09, up from $3.27 in the year-ago quarter. On average, analysts were expecting EPS of $4.71.

In Amazon's second quarter, analysts estimate the company will post EPS of $5.56 -- up from $5.07 in the second quarter of 2018. This consensus forecast seems reasonable in light of guidance for operating income between $2.6 billion and $3.6 billion. Given that management's operating income guidance typically proves conservative, actual operating income could easily come in at the high end of this range, putting the profitability metric well above operating income of $3 billion in the second quarter of 2018. Operating income at the high end of Amazon's guidance range, therefore, would likely translate to meaningful EPS growth.

AWS revenue growth

Finally, investors should check in on Amazon's cloud computing business, Amazon Web Services (AWS). Accounting for about half of the company's operating income, continued strong growth in the segment is key to the stock's long-term performance.

AWS revenue increased 41% year over year in Q1, down from 45% growth in the fourth quarter of 2018 and 47% growth for the full year of 2018. Given that the segment has decelerated meaningfully recently, investors should look for this deceleration to start moderating or even come to a halt. If growth continues to slow meaningfully every quarter, investors may need to reevaluate the segment's growth prospects.