The disclosure relates to systems, methods, and devices for processing payment transactions between a user and a merchant using a messaging bot. In particular, a commerce system allows the user to initiate a communications session with a messaging bot associated with the merchant using natural language. One or more embodiments use natural language processing to analyze messages from the user to the messaging bot, and from the messaging bot to the user, to identify a product and a request to purchase the identified product. Based on the identified product and the request to purchase the product, one or more embodiments initiate a payment transaction on behalf of the user based on a natural language conversation and without redirecting the user away from the communications session. Additionally, one or more implementations provide a payment initiation message from the messaging bot to the user indicating that the payment transaction was initiated.