The kids are back in school, every shopping center smells of pumpkin spice, and the last earnings season of the calendar year is about to kick off. At this juncture, the tech-heavy Nasdaq Composite (^IXIC 2.02%) stock market index has gained 30% year-to-date but also traded sideways in the last two months.

Many potent tech stocks lurk in Wall Street's autumn leaf piles with modest share prices. Let me show you some of my favorite hidden gems in this brisk October air.

Atlassian

Business management software may not sound like an exciting growth market, but Atlassian (TEAM -9.56%) makes it work. The stock is down 4% over the last month but up 60% year-to-date, highlighting the potential for tremendous growth and the sluggish performance in recent weeks.

The Australia-based company behind popular collaboration tools such as Jira, Confluence, and Trello has been through some rocky roads. The conversion from traditional software licenses to cloud-based software-as-a-service (SaaS) subscription plans is largely complete, with 96% of active customers using the cloud service.

The company delivers stellar growth even in this challenging economy. Fourth-quarter revenues rose by 23.5% year over year while Atlassian's operating cash flow saw a 27% increase.

And Atlassian is quick to latch onto new market opportunities. In the wake of the ChatGPT boom, Atlassian has already published a generative AI platform, adding an AI-powered personal touch to many different software tools.

The stock doesn't look cheap by traditional metrics, trading at 94 times forward earnings projections and 15 times trailing sales. However, you're paying a premium for a top-notch growth stock -- and it was even more costly before the inflation-driven economic crisis.

And it's getting harder and harder to ignore this rising software star. Atlassian's services are transforming the way people work and collaborate. Yet, the growth story is only getting started and the bulk of the market opportunity still lies ahead.

Roku

I get why Roku (ROKU -10.29%) is on fire sale. The media-streaming technology veteran operates in a difficult economy as people aren't buying a ton of new smart TV sets and companies aren't spending a ton of money on digital marketing campaigns. And Roku's management has decided to absorb most of that financial pain instead of passing the buck to its customers. So Roku's bottom line is printed in a crimson shade of red and even the all-important revenue growth has slowed down in recent quarters.

So Roku's stock price is up 79% in 2023 but down 13% over the last month. All in all, the stock is down by a hair-raising 85% from the all-time highs of 2021. All of this makes sense -- if you're only skimming the company's financial releases and long-term plans.

But if you dig deeper, I think you'll agree that Roku's stock is brutally undervalued today.

The lack of bottom-line profit was a conscious decision, boosting Roku's user reach in an economic environment where most rivals are playing it safe. The company paid off the last pennies of long-term debt in the spring of 2023. In other words, Roku is fantastically prepared to tackle a few more quarters of slow ad sales. The long-term target market is orders of magnitude larger than the current count of 73.5 million active accounts. And Roku's global growth story is in its infancy as the company applies the lessons learned in North America to largely unexplored media-streaming territories in Europe, South America, and Asia.

I keep recommending this stock to anyone who would listen. This is arguably the best buy in this difficult market, and I have doubled down on Roku several times in the last two years. And here I am again, extolling Roku's virtues for your benefit.