Abstract: Disclosed is a technology for seamless initiation of a financial service, such as a payment transaction, by sending a communication message. The disclosed technology can be used, for example, to send payment from a person (e.g., a consumer) to another over e-mail without requiring any sign-up or login procedure. In at least one embodiment, the technology includes receiving a service request email generated by a native email application on a consumer's device, verifying the email using information included in the email, and initiating the service as requested based on the information. Various embodiments of the disclosed technology enable a simplified payment transaction system for ordinary consumers without the hassle of having to sign up, to remember a user account and a password, and to login for sending or receiving every payment transaction, while not sacrificing the essential security feature of authenticating the user for every payment transaction.