Pinterest's inspiration boards are transforming into shoppable catalogs. Today the company announced "buyable pins," which let you complete purchases from inside the app. The company's first foray into e-commerce, which rolls out at the end of the month, comes as 80 percent of Pinterest users are already buying things on their phones. "People want to buy things on Pinterest," says Ben Silbermann, the company's co-founder and CEO.

Pinterest is valued at more than $11 billion under the expectation that it could become a thriving platform for e-commerce. In a way, it already is — many users create boards full of things they want and go on to buy them elsewhere. But currently, Pinterest's only way to make money from those users is from "promoted pins," its form of native advertisement.

The design for buyable pins places a big blue "buy this" button next to the traditional red "pin it" button in the mobile app. You can buy items using a credit card or with Apple Pay. Commerce will become available first on the Pinterest app for iPhone and iPad later this month. Android will come later, Silbermann says.

Interestingly, Pinterest won't be taking a cut of the sale — the company says it wants to ensure the largest selection of products, and to make users comfortable that they won't be charged a higher price on Pinterest than on the retailer's website. Instead, retailers will pay to have their pins featured in users' feeds. And given Pinterest's understanding of their users' interests, those promoted pins will likely be expensive.

More than 2 million items will be available for purchase from the start. Pinterest's initial retail partners include Macy's, Nordstrom, and Neiman Marcus. Pinterest has not yet what cut it will take of transactions that take place on the service. The news comes on the same day that Instagram is adding "buy" buttons to ads.