While Amazon's dominance in the U.S. can make this hard to believe, e-commerce sales are still just 10 percent of retail sales overall in the U.S., according to estimates from research firm eMarketer. Now, traditional retailers and direct-to-consumer outlets are in pursuit of growth through e-commerce.

Enter GreyOrange, which makes robots and AI software to help retailers compete with Amazon, especially on variety and speed of delivery.

The company's robots, dubbed the Butler and PickPal, are a self-driving cart and a robotic arm that can help warehouse operators automate some of their employees' most physically challenging tasks. The robots assist in repetitive sorting, picking items off shelves and carting heavy loads around a warehouse.

The robots draw frequent comparisons to warehouse robots made by Amazon Robotics. However, GreyOrange co-founder Samay Kohli says his company's systems are distinct in that they can go to work right out of the box and can learn from their surroundings and activity in warehouses. The robots can also share data with one another.

GreyOrange's clients are mostly retailers with both physical and online stores, as well as apparel makers, third-party logistics providers and consumer electronics companies, according to co-founders Samay Kohli and Akash Gupta.