(Telecompaper) Twitter users are closer to making purchases via the messenging service after the company said it has joined with several e-commerce sites to make it easier for merchants of all sizes to sell their wares directly via its service, the Wall Street Journal reported. Local boutiques and big brands using online commerce platforms Shopify, Bigcommerce and Demandware will be able to add a "buy button" to a tweet allowing users to click through to purchase a product. Retailers can also turn regular tweets with a buy button into an ad. The buy button will only be available to US-based merchants. The announcement comes a few weeks after Twitter joined up with online payments startup Stripe's Relay service, which lets merchants sell products through a buy button that developers can easily place inside their apps.