The front-end app you develop will interact with an AI application. That AI application—usually a hosted service—is the component that interprets user data, directs the flow of the conversation and gathers the information needed for responses. You can then implement the business logic and any other components needed to enable conversations and deliver results.
Simple chatbots, or bots, are easy to build. In fact, many coders have automated bot-building processes and templates. The majority of these processes follow simple code formulas that the designer plans, and the bots provide the responses coded into it—and only those responses. Simplistic bots (built in five minutes or less) typically respond to one or two very specific commands.
2a : a computer program that performs automatic repetitive tasks : agent sense 5 Several shopping "bots" will track down prices for on-line merchandise from a variety of vendors.— Sam Vincent Meddis especially : one designed to perform a malicious action These bot programs churn away all day and night, prodding at millions of random IP addresses looking for holes to crawl through. — Jennifer Tanaka
The process of building, testing and deploying chatbots can be done on cloud based chatbot development platforms offered by cloud Platform as a Service (PaaS) providers such as Yekaliva, Oracle Cloud Platform, SnatchBot and IBM Watson.   These cloud platforms provide Natural Language Processing, Artificial Intelligence and Mobile Backend as a Service for chatbot development.
Using this method, you can manage multiple funnels of content upgrades, and even convince your users to take the next step in the buyer journey directly within Messenger. In the example below I just direct the user to subscribe to content recommendations via Messenger, but you could push them to book a meeting with a sales rep, take a free trial or directly purchase your product.
Modern chatbots are frequently used in situations in which simple interactions with only a limited range of responses are needed. This can include customer service and marketing applications, where the chatbots can provide answers to questions on topics such as products, services or company policies. If a customer's questions exceed the abilities of the chatbot, that customer is usually escalated to a human operator.
The classic historic early chatbots are ELIZA (1966) and PARRY (1972). More recent notable programs include A.L.I.C.E., Jabberwacky and D.U.D.E (Agence Nationale de la Recherche and CNRS 2006). While ELIZA and PARRY were used exclusively to simulate typed conversation, many chatbots now include functional features such as games and web searching abilities. In 1984, a book called The Policeman's Beard is Half Constructed was published, allegedly written by the chatbot Racter (though the program as released would not have been capable of doing so).