How to Spy on Competitor Sales Volumes

Want to know how well your competitors are really doing?

Here’s a little trick: try adding 9,999 units to your cart on their website.

Many eCommerce systems will respond with the actual number they have in stock. For example, if they’ve only got 42 left, it’ll tell you. If they’ve got 1,800? You’ll know that too.

Now do that once a week for key products.

Over time, you’ll start to see sales velocity—how quickly they’re shifting stock. And that tells you three things:

1. What’s in demand
2. Whether they’re outselling you on shared lines
3. How many they purchase in one PO (as the stock count will jump up that week)

If you see they’re moving more volume than you on a product you also sell, don’t panic—investigate.

• Are they running regular promotions?
• Are they featuring it on social media or banners?
• Are they winning on price, or simply doing a better job with visibility?

This isn’t about copying—it’s about learning. Their stock levels reveal customer demand trends. And once you know what’s moving, you can adjust your own strategy—whether that’s with pricing, stock levels, or marketing focus.

A little digital spying goes a long way.