As investors gear up for more earnings reports from tech giants like Facebook and Apple this month, one much smaller tech start-up may be the most interesting company in tech to watch. Shopify (NYSE:SHOP) -- a provider of a cloud-based e-commerce platform -- has been on a tear, rising 67% year to date and more than 400% over the past three years.

Its soaring stock price, rapidly rising total revenue, and accelerating merchant solutions revenue are morphing Shopify into a growth stock in its purest form. Of course, the curse of any successful growth stock is the high expectations that come along with its premium valuation. That's what will make Shopify's second-quarter earnings release later this month particularly interesting.

Ahead of Shopify's second-quarter update, here's a preview of three metrics investors will want to check on when the results go live.

Shopify e-commerce platform on a smartphone, laptop, and tablet

Image source: Shopify.

1. Revenue growth

As a growth stock, investors will likely check in on Shopify's revenue growth before anything else. If revenue growth decelerates more rapidly than expected, this could cause investors to lose confidence in Shopify's longer-term growth potential.

In Shopify's most recent quarter, revenue increased 68% year over year. Given that this growth was a deceleration from 71% year-over-year growth in Q4 and 72% growth in Q3, revenue will likely decelerate again in Q2. Indeed, the consensus analyst estimate calls for second-quarter revenue of $235 million, implying a 55% year-over-year increase in revenue.

Analysts' consensus estimate falls at the high end of management's guidance range for second-quarter revenue between $230 million and $235 million.

2. Subscription solutions revenue

Accounting for 47% of total revenue, Shopify's first-quarter subscription solutions revenue increased 61% year over year to $100.2 million. Shopify said this growth was driven by strong growth in the number of merchants subscribing to its platform.

Representing a meaningful deceleration compared to the 67% growth in subscription solutions revenue Shopify posted in its fourth quarter of 2017, investors should look to see how much this segment's year-over-year growth rate will continue to decelerate in Q2.

3. Merchant solutions revenue

Shopify's merchant solutions segment saw a nice uptick in its growth rate in Q2, accelerating from 74% year-over-year growth in Q4 to 75% growth in Q1.

Merchant solutions revenue growth in Q1 was driven by a 64% increase in gross merchandise volume (GMV) for Shopify Payments and revenue from shipping and Shopify Capital that more than doubled, management said in the company's first-quarter earnings call. 

Shopify Capital provided $60.4 million worth of merchant cash advances in Q1, up significantly from $19.9 million in the first quarter of last year. In addition, cumulative cash advances to merchants reached $230 million, up from $63.5 million in the first quarter of 2017.

Can Shopify keep up its strong momentum in merchant solutions revenue? Accounting for more than half of total revenue, growth close to Q1's 75% growth could mean total revenue comes in above Shopify's guidance range for the quarter.

Shopify is scheduled to report its second-quarter results before market open on Tuesday, July 31. The company will host a conference call to discuss its results at 8:30 a.m. EDT on the same day. 

Daniel Sparks owns shares of Apple. The Motley Fool owns shares of and recommends Apple, Facebook, and Shopify. The Motley Fool has the following options: long January 2020 $150 calls on Apple and short January 2020 $155 calls on Apple. The Motley Fool has a disclosure policy.