The power of Twitter as a way to sell stuff is all about the chatter. It’s word-of-mouth for the whole world. But if global chit-chat greases the way for marketers hoping to make their products known, the part that comes next—actually buying the thing—quickly gets awkward, especially on your phone, where you’re most likely to be using Twitter in the first place.

Even today, when mobile devices have become screens we turn to first for so much of our personal computing, only about 15 percent of e-commerce sales happen on the phone, according to Patrick Collison, co-founder of digital commerce startup Stripe. As Collison points out, the web is still the main venue for making purchases online, and the mobile web, at least for shopping, is kind of a pain.

“The obviousness and significance of the problem has been on a lot of folks’ minds,” Collison said during a presentation in San Francisco today. Well, at least the people in the business of trying to figure out how to capture your attention—and money—on mobile devices. And Twitter provides an especially instructive example. Let’s say you see something you like in a tweet; maybe you click a link that opens a browser, maybe you have to open a browser yourself and search Google. From there, you have to find the product, typically put it in a cart, enter your credit card number, your address, and on and on. “It’s like an obstacle course before people can give you money,” Collison said.

Stripe is now valued at $5 billion thanks to its success in eliminating the obstacles to moving money online. Anyone with even modest technical skills can start accepting credit cards online within 10 minutes of setting up a Stripe account. Now Stripe has brought the same slickness that has made it such a success in making and taking payments to the actual stuff you’re buying and selling online.

You don’t have to know what an application programming interface is to appreciate what Stripe’s new Relay API can do. Now anyone with a Stripe account can build what amounts to a virtual catalog of items that, for starters, they can use to sell anything on Twitter without the customer ever having to leave Twitter’s app.

“We have 50 million-plus users every month who are tweeting some signal of intent with the words ‘I want’ or ‘I need,'” said Twitter’s head of commerce, Nathan Hubbard. By integrating Stripe’s Relay platform, Hubbard said, Twitter is able to collapse the distance between that desire and the ability to fulfill it.

For Stripe and the sellers using it, the power of Relay is obvious. Right now, sellers can use Relay to sell in-app not only on Twitter but on fashion marketplace Shopstyle; mobile shopping app Spring; and via ad-tech platform InMobi. For Stripe, meanwhile, switching on the API for other platforms feels like a simple path to exponential growth (think Instagram and Facebook, which has already experimented with Stripe for payments).

Becoming a more comprehensive destination for buying and selling can only help Twitter, as well. For a company whose recent struggles stem in part from its seeming inaccessibility to casual users, “buying stuff” is a use case that’s easy to understand. And advertisers will no doubt appreciate the ability to pay for tweets that have the potential to convert into a sale in one simple step.

That said, tweets seem more like a medium for quick impulse buys than the kinds of big-ticket purchases consumers are more likely to make only after poring over research and reviews on the web. Buying straight from brands can also be an inconsistent experience. For some users, a few extra taps on the phone are worth the time when they know that just as surely as the sun will rise twice in two days’ time, their Amazon Prime deliveries will arrive at their door. When it comes to one-click shopping, Bezos is still the one to beat.