Systems and methods are provided to facilitate online transactions via mobile communications. In one aspect, a system includes a data storage facility to store an account identifier of a user and a phone number of the user and an interchange coupled with the data storage facility. The interchange includes a common format processor and a plurality of converters to interface with a plurality of different controllers of mobile communications. The converters are configured to communicate with the controllers in different formats and the converters are configured to communicate with the common format processor in a common format to facilitate electronic payment transactions using the account identifier.