Sure, competition online is intensifying, as web leader Amazon.com Inc. now owns roughly a third of the online retail market in the United States. But new data from the just-released Internet Retailer 2016 Second 500 Guide shows a healthier-than-ever middle tier in online retail, as small retailers are maintaining impressive growth rates despite a myriad of challenges.

In fact, the merchants ranked in the Second 500 Guide—or those that sold between $1.7 million and $28.3 million online last year—collectively grew e-commerce sales 14.9% to $6.992 billion from $6.087 billion in 2014. That’s the first time since Internet Retailer began tracking the mid-market of online retailing market in 2011 that the small and midsize retailers in the Second 500 have outgrown their much larger competitors ranked in the Top 500 Guide. Led by Amazon, those larger merchants collectively grew 13.5% last year—their slowest rate in nine years. Second 500 merchants also outpaced the U.S. e-commerce market as a whole, which grew 14.6% last year, according to the U.S. Commerce Department.

Growth varies by category and type of retailer. The apparel category is doing well, for example, with 18.1% collective growth among the 111 Second 500 merchants that primarily sell clothing and accessories, compared with the books/music/video category (largely dominated by Amazon and Apple Inc.), whose 13 Second 500 retailers grew 4.8% collectively last year.

Comparing category growth numbers among large retailers and small retailers—Top 500 versus Second 500—also reveals areas where the latter perform especially well. The smaller computer and electronics retailers, for example, outgrew their larger competitors, growing at 10.3% versus 3.4% among the Top 500. Many of the fastest growers in this category operate in niche segments untapped by larger players like Best Buy Co. Inc. (No. 12) or Amazon.

For example, FlexShopper (No. 607), operates a rent-to-own online business that allows consumers to lease popular consumer electronics items by filling out an online credit application and making monthly payments. The merchant grew more than 300% last year to roughly $20.7 million in web sales.

Similar to previous years and to trends among the larger retailers of the Top 500, web sales growth among smaller online players is concentrated most heavily among those that sell only online. The 299 web-only retailers in the Second 500 grew collective web sales 16.6% to $4.15 billion from $3.56 billion, compared with retail chains—whose online sales increased 15.2%—consumer brands that grew 11.7% and catalogers, which grew 8.5%.

Still, no matter the category or the business model, small and midsize web merchants do not have it easy. Nearly all of them report facing headwinds, including competition from more online players, rapid changes coming from major technology players like Google Inc., and increasing demands from online consumers for fast delivery and free shipping, mobile-optimized everything and a shopping experience tailored to their wishes. The ones that overcome these challenges most effectively survive and flourish online by finding an edge—a sweet spot, if you will.

Find out which ones are doing just that, and—most importantly—how they’re doing it in this latest edition of the Second 500 Guide, now in its 6^th year.

Included in the print, digital and database versions of the Second 500 Guide are the following:

• Rankings and data-filled profiles of 500 fast-growing online retailers in North America that represent the fast-growing midtier in e-commerce, including operational data on conversion rates, average order values, e-commerce executive contact names and technology vendors used.
• For the first time ever, an Internet Retailer Performance Score, which rates all merchants in the midtier by the success of their online strategy in comparison to their peers and the market as a whole.
• Three-year web sales figures (dollar amounts included in the database version only)
• In-depth analysis of the key trends in the market, and strategic success stories of some of the web’s most innovative retailers
• Multiple charts and graphs, including a list of the fastest-growing e-retailers among the midtier, a look at monthly paid search spending features on some of the largest players, and rankings by product category.