Costco's app is finally starting to show what's in stock at your warehouse

• Costco has been quietly rolling out a new product availability feature on its app and website.
• Available in select markets, the tool lets shoppers know if a product is in-stock at a warehouse.
• Costco is still playing catch-up to its rivals, whose apps are more robust.

Costco is taking some of the guesswork out of shoppers' warehouse trips .

The wholesale club has been quietly rolling out a new product availability feature on its mobile app and website in recent weeks that shows whether an item is in-stock at a particular location.

Available in select markets (including the area near Costco's headquarters near Seattle), the tool lets shoppers know if a product is at a local warehouse, though it stops short of showing where the item can be found within the building.

In an interesting twist, Business Insider was able to view availability information for warehouses in Wisconsin after updating the primary location setting in the website and app to Issaquah, and then using the "Check Nearby Warehouses" option to find a closer warehouse.

The long-desired feature has been enthusiastically received by shoppers on social media.

"I just looked out the window to see if a pig flew by. My Costco app has LOCAL INVENTORY SEARCH. Amazing," X user Neil Enns posted last week.

Never one to be on the vanguard of technology, Costco's app is still years behind other major retailers, whose apps are more robust .

Walmart and Target each will tell app users where to find items in their stores, as well as how many they might expect to see when they get there.

Home Depot and Lowe's have also invested considerable resources into helping shoppers identify the right aisle and bin numbers in their sprawling warehouses to find a particular screw needed to finish a project.

Even Ace Hardware, where most locations are locally owned and operated, allows shoppers to check if an item is on the shelf of their favorite store before heading out the door.

Where Costco lags most severely is behind its largest warehouse competitor, Walmart-owned Sam's Club, whose shoppers can use the app not only to find items, but scan, pay, and roll through the exits without stopping .

Costco shoppers have largely forgiven the company's slow adaptation to the 21st Century, but this new feature is likely to be a welcome one.