The process of building a chatbot can be divided into two main tasks: understanding the user's intent and producing the correct answer. The first task involves understanding the user input. In order to properly understand a user input in a free text form, a Natural Language Processing Engine can be used. The second task may involve different approaches depending on the type of the response that the chatbot will generate.
Since 2016 when Facebook allows businesses to deliver automated customer support, e-commerce guidance, content and interactive experiences through chatbots, a large variety of chatbots for Facebook Messenger platform were developed. In 2016, Russia-based Tochka Bank launched the world's first Facebook bot for a range of financial services, in particularly including a possibility of making payments.  In July 2016, Barclays Africa also launched a Facebook chatbot, making it the first bank to do so in Africa. 
Smooch acts as more of a chatbot connector that bridges your business apps, (ex: Slack and ZenDesk) with your everyday messenger apps (ex: Facebook Messenger, WeChat, etc.) It links these two together by sending all of your Messenger chat notifications straight to your business apps, which streamlines your conversations into just one application. In the end, this can result in smoother automated workflows and communications across teams. These same connectors also allow you to create chatbots which will respond to your customer chats…. boom!
For designing a chatbot conversation, you can refer this blog — “How to design a conversation for chatbots.” Chatbot interactions are segmented into structured and unstructured interactions. As the name suggests, the structured type is more about the logical flow of information, including menus, choices, and forms into account. The unstructured conversation flow includes freestyle plain text. Conversations with family, colleagues, friends and other acquaintances fall into this segment. Developing scripts for these messages will follow suit. While developing the script for messages, it is important to keep the conversation topics close to the purpose served by the chatbot. For the designer, interpreting user answers is important to develop scripts for a conversational user interface. The designer also turns their attention to close-ended conversations that are easy to handle and open-ended conversations that allow customers to communicate naturally.
Training a chatbot happens at much faster and larger scale than you teach a human. Humans Customer Service Representatives are given manuals and have them read it and understand. While the Customer Support Chatbot is fed with thousands of conversation logs and from those logs, the chatbot is able to understand what type of question requires what type of answers.
Each student learns and absorbs things at a different pace and requires a specific methodology of teaching. Consequently, one of the most powerful advantages of getting educated by a chatbot is its flexibility and ability to adapt to specific needs and requirements of a particular student. Chatbots can be used in a wide spectrum, be it teaching people how to build websites, learn a new language, or something more generic like teach children Math. Chatbots are capable of adapting to the speed at which each student is comfortable - without being too pushy and overwhelming.
The goal of intent-based bots is to solve user queries on a one to one basis. With each question answered it can adapt to the user behavior. The more data the bots receive, the more intelligent they become. Great examples of intent-based bots are Siri, Google Assistant, and Amazon Alexa. The bot has the ability to extract contextual information such as location, and state information like chat history, to suggest appropriate solutions in a specific situation.
What began as a televised ad campaign eventually became a fully interactive chatbot developed for PG Tips’ parent company, Unilever (which also happens to own an alarming number of the most commonly known household brands) by London-based agency Ubisend, which specializes in developing bespoke chatbot applications for brands. The aim of the bot was to not only raise brand awareness for PG Tips tea, but also to raise funds for Red Nose Day through the 1 Million Laughs campaign.
Many expect Facebook to roll out a bot store of some kind at its annual F8 conference for software developers this week, which means these bots may soon operate inside Messenger, its messaging app. It has already started testing a virtual assistant bot called “M,” but the product is only available for a few people and still primarily powered by humans.
Feine, J., Morana, S., and Maedche, A. (2019). “Leveraging Machine-Executable Descriptive Knowledge in Design Science Research ‐ The Case of Designing Socially-Adaptive Chatbots”. In: Extending the Boundaries of Design Science Theory and Practice. Ed. by B. Tulu, S. Djamasbi, G. Leroy. Cham: Springer International Publishing, pp. 76–91. Download Publication
Perhaps the most important aspect of implementing a chatbot is selecting the right natural language processing (NLP) engine. If the user interacts with the bot through voice, for example, then the chatbot requires a speech recognition engine. Business owners also have to decide whether they want structured or unstructured conversations. Chatbots built for structured conversations are highly scripted, which simplifies programming but restricts the kinds of things that the users can ask.
Malicious chatbots are frequently used to fill chat rooms with spam and advertisements, by mimicking human behavior and conversations or to entice people into revealing personal information, such as bank account numbers. They are commonly found on Yahoo! Messenger, Windows Live Messenger, AOL Instant Messenger and other instant messaging protocols. There has also been a published report of a chatbot used in a fake personal ad on a dating service's website.
As digital continues to rewrite the rules of engagement across industries and markets, a new competitive reality is emerging: “Being digital” soon won’t be enough. Organizations will use artificial intelligence and other technologies to help them make faster, more informed decisions, become far more efficient, and craft more personalized and relevant experiences for both customers and employees.
Another option is to integrate your own custom AI service. This approach is more complex, but gives you complete flexibility in terms of the machine learning algorithm, training, and model. For example, you could implement your own topic modeling and use algorithm such as LDA to find similar or relevant documents. A good approach is to expose your custom AI solution as a web service endpoint, and call the endpoint from the core bot logic. The web service could be hosted in App Service or in a cluster of VMs. Azure Machine Learning provides a number of services and libraries to assist you in training and deploying your models.
Human touch. Chatbots, providing an interface similar to human-to-human interaction, are more intuitive and so less difficult to use than a standard banking mobile application. They doesn't require any additional software installation and are more adaptive as able to be personalized during the exploitation by the means of machine learning. Chatbots are instant and so much faster that phone calls, shown to be considered as tedious in some studies. Then they satisfy both speed and personalization requirement while interacting with a bank.