It can be tough for small businesses to go head-to-head with the ecommerce juggernaut that is Amazon.com Inc., but shipping startup Shippo wants to give businesses a fighting chance by making it easy to fulfill online orders in real time.

Shippo announced today that its platform is going strong with a 71 percent year-over-year growth per customer, and the company also revealed that it quietly closed a $20 million Series B funding round earlier this year.

The funding round was led by Bessemer Venture Partners, and it included participation from Union Square Ventures, SoftTech VC, VersionOne Ventures and 500 Startups. The new financing brings Shippo’s total funding to date to $29 million.

Founded in 2013, Shippo’s platform offers businesses an application programming interface and dashboard that allow them to integrate order fulfillment and shipping directly into their existing ecommerce sites. According to Shippo, the e-commerce industry is expected to double to more than $4 trillion in just three years, and the company said existing delivery infrastructure is struggling to keep up. That may not be a big deal for multibillion-dollar companies like Amazon, but it is a problem for smaller businesses. Shippo believes its platform can help close that gap.

“Shippo customers are nearly doubling their shipping volume with us in any single year,” said Laura Behrens Wu (pictured), co-founder and chief executive of Shippo. “Our customers are able to focus on creating a unique brand experience for their customers, while we handle shipping by providing the best delivery option — always.”

Shippo’s primary targets are small to midsized businesses, but the startup has also scored partnerships with a few major companies, including eBay Inc., Tuft & Needle, GOAT, Ipsy, Loot Crate and Marley Spoon by Martha Stewart. According to the company, its shipping platform is now used by more than 15,000 customers.

Shippo has a few competitors that are also looking to give smaller businesses a leg up in shipping, including a few that support one of Amazon’s hardest-to-beat features: same-day shipping. Although Shippo does offer two-day and overnight delivery options, the company does not currently appear to support same-day deliveries, which are already available for free on Amazon Prime orders in more than 5,000 cities.

Photo: Shippo