After months of preparation, Twitter now has a payments system powered by Stripe

Twitter is – at long last – introducing e-commerce into its tweets. The “buy this product” button has been rumored for months, but Monday it was confirmed by the social media network. An initial test batch of mobile users will be able to purchase within a tweet itself, without ever leaving the application. Down the line, Twitter will expand it to desktop and more users.

The “buy” button is being tested out in the [company]Twitter[/company] wild with three initial partners – social shopping platform Fancy, art and digital content marketplace Gumroad and music merchandise site Musictoday. Twitter announced a range of individual sellers with the partnership, from Demi Lovato to Home Depot to Burberry.

It’s a good day to be [company]Stripe[/company]. The payments processing startup, which competes with the dream team of [company]PayPal[/company] and [company]Braintree[/company], will be powering Twitter’s payment processing system. It will most likely get a cut from each transaction, although neither Stripe nor Twitter has disclosed how much.

It’s the reckoning moment for e-commerce on Twitter, and none too soon as its rival [company]Facebook[/company] starts testing out its own buy button. Let the selling battle begin.