Like many of its large-cap tech peers, Amazon's stock has slumped since the fall of 2018 amid broader market volatility.

Despite any slump, many Amazon (AMZN) - Get Report investors believe there's much to feel good about in 2019. Bulls anticipate that the commerce and cloud giant will sustain its dominance in online retail while extending its reach in other lines of business like advertising, video and its growing Alexa ecosystem.

That doesn't mean there aren't pitfalls ahead -- here are some of the biggest potential challenges facing Amazon this year.

1. Keeping Up E-commerce Growth

As noted in a recent report from by Evercore ISI's Anthony DiClemente, growth in Amazon's legacy, first-party e-commerce business has lost some of its steam, with Amazon posting 10% growth year-over-year in the segment "While other higher margin business lines have taken over the growth mainly from the Online Stores unit, this operating segment still makes up >50% of revenue, and a more substantial slowdown would weigh on consolidated revenue growth," he wrote.

2. International Performance

Some of Amazon's lackluster October earnings was accounted for by weak returns in Amazon's international segments, which posted lighter-than-expected growth at 15% on a constant currency basis versus 21% the previous quarter. Amazon CFO Brian Olsavsky pinned some of the weak growth on the timing of India's Diwali holiday as well as Amazon's purchase of Souq.com on an earnings call, but investors will be on the lookout for how Amazon fares internationally this year.

3. Keeping Rivals at Bay

Amazon may be the undisputed leader in e-commerce, but formidable rivals like Walmart (WMT) - Get Report could get more aggressive in their efforts to siphon market share from Amazon. In a December report, Edgewater Research's Daryl Boehringer pointed out that Amazon pulled back on promotions and price matching versus rivals last year, and in turn, "brick-and-mortar competition (namely Walmart) appears to be taking advantage of Amazon's less aggressive stance," he wrote, citing an apparent profit focus, rather than a growth focus, by Amazon in recent quarters. For investors, saber-rattling from other retail giants, ever eager to deepen their online presence, is worth keeping an eye on in 2019.

4. Balancing Investments vs. Profits

With Amazon's newer efforts in areas like health care consistently in the news, Evercore's DiClemente wrote that a fresh wave of investment by Amazon could be imminent in 2019. "Amazon is obviously notorious for plowing earnings back into the business," he wrote. "With new initiatives like healthcare, payments, logistics, etc. continuing to make headlines, there is some concern amongst investors that the next aggressive investment inflection could be just around the corner." Although investing in new technologies and lines of business can reap rewards down the road, an aggressive investment ramp-up could also weigh on Amazon's earnings growth story in the coming year, according to DiClemente.

5. Dealing With More Intense Government Scrutiny

With a new congress just settling in, fresh scrutiny of tech giants could also pose issues down the road. The EU and other countries like France have stepped up their regulation and taxation efforts of major tech companies, including Amazon. In the U.S., Amazon's HQ2 expansion -- and the large tax breaks it received -- became a flash point for criticism last year of Amazon's size and influence over policymakers. And with a changing of the guard in Congress, privacy and antitrust concerns will be key issues to watch as lawmakers on both sides of the aisle step up their scrutiny of the power of Big Tech.

Amazon is a holding in Jim Cramer's Action Alerts PLUS member club. Want to be alerted before Jim Cramer buys or sells AMZN? Learn more now.