How to design and build an SMS chatbot

An SMS chatbot is a software program that can automatically send or reply to text messages, and by being trained to understand intent can even have ‘conversations’ with people over SMS.

Text chatbots are commonly used by businesses as a way of automatically providing information and answering questions from customers. They can be deployed to help in a number of areas.

While chatbots can be effectively deployed on all sorts of digital channels, there are a number of reasons to include text messages in the mix.

There are two main types of SMS chatbot, but they are not distinct as elements of both can be incorporated into the same text chatbot.

These chatbots are designed to enable the exchange of information using YES/NO answers or a pre-configured menu of options for users to select from. They are the quickest and easiest to set up but can be incredibly useful for use cases where a quick and simple answer is required, for example answering day-to-day queries that customers would previously have called a contact center to answer. Anything from store opening hours, product availability, and account balances can be provided via a simple set of options.

These are more sophisticated chatbots that can be designed to provide a more conversational experience for people interacting with them. They take longer to build as they use natural language processing (NLP) and need to be ‘trained’ to understand multiple words, phrases and user intents. While these conversational chatbots can be deployed on the SMS channel, the relative cost and speed of typing text on a mobile device make them better suited for web and chat app channels.

Before you decide if a text chatbot is right for your use cases, refer to our detailed table that compares SMS bots with chatbots available on digital channels like WhatsApp, Messenger, and Viber.

Our worked example uses the free trial version of our chatbot building tool Answers.

To follow the steps, just sign up for your own free account using this link. You get full access to Answers with the ability to build SMS chatbots as well as bots for WhatsApp, Messenger, Viber, and web.

Note that to actually deploy your SMS chatbot will require adding credits to your account.

To get started building your first SMS chatbot, log into your account and select the Answers icon from the panel on the left.

Then click the Try for Free button.

Under Basic setup, click Your first chatbot and then from under Start from template or create new select CREATE CHATBOT.

This page displays a number of pre-built templates that you can use to form the basis of your chatbot, or you can select Start from scratch to create your own.

The final setup step is to give your chatbot a name and select SMS as the deployment channel. There is no need to specify a Sender at this point, although this will need to be configured before the chatbot is made live.

Answers’ interface provides a drag and drop canvas where you can build up your chatbot flow by dragging elements from the panel on the right-hand side. Simply drag on the element that you want and then configure it using the settings on the right.

In our example we will only be using a few of Answer’s basic features, but you are free to experiment as much as you like with more advanced options. These are fully documented in our online help, which includes a number of useful tutorials:

Due to the cost of sending SMS messages, chatbots deployed by SMS should be designed to achieve a specific purpose with as few messages backwards and forwards as possible.

It is also important that the value of the interaction is clear to the customer up front so that they are willing to invest their time and money in the process.

With this in mind, the first message in the interaction is important as it needs to catch the person’s attention and make the purpose of the message crystal clear.

Drag on a Text element from the Chatbot sends menu and configure a welcome message.

When sending multiple messages in a sequence, it is best practice to include a Delay between each one to give the user time to read and absorb the previous message to avoid overwhelming them with information.

Simply drag on a Delay element from the Chatbot actions menu and set a suitable delay according to the length of the previous message. You can always fine-tune delays during the testing phase.

In our welcome message we have made it clear what the intent of the chatbot is. We are asking the person if they would like to book tickets and there are only two answers – YES or NO.

We therefore use a User Input element to capture their response so that we can create the appropriate flows depending on their choice.

The next step is to add a Go to dialog element for each reply, so that we can deal with each intent separately. At this point you could add as many options as you like, but this would require a separate flow for each option, so it is best to keep it simple.

In our example we are just creating flows for the answers YES and NO, but we could have added additional options like ‘Remind me later’.

This is the point where the chatbot delivers on its promise and is configured to perform an action that delivers value to the user.

If the user selects NO then we simply sign off with a friendly goodbye, but if they select YES then that would trigger the action – in this case to reserve tickets.

The next step would require an integration with a third-party booking system, which is no problem to do via the API. In our example we can send the person a payment link by SMS, although any supported payment system could be used.

When building an SMS chatbot you should always confirm with the person that the intent has been achieved. If the person has not achieved their goal, you should provide them with an alternate path, so they are not left in limbo and don’t waste any further SMS messages.

You can then sign off the chat or loop them back to the beginning.

To close and reset the chatbot interaction add a final Close session attribute. This can also optionally delete any saved data – or it can be copied to your customer database to enrich future interactions with the person.

Answers provides a Simulation option that can be used to test your chatbot flow and make final adjustments to ensure a good user experience. If you have missed any steps, or have misconfigured any dialogues, then these will be flagged before the simulation can be used.

This is simple example of a rule-based SMS chatbot that allows the exchange of information between the business and customer using a combination of simple YES and NO options and direct multiple-choice questions.

Using Answers, you can go on to create highly sophisticated text chatbots that use natural language processing to understand customer intent and to facilitate conversational interactions via text. Take a look at the following video which provides a good introduction to building chatbots with Answers.