Table 5.

Codes, number of occurrences, and examples of positive feedback regarding usability (we translated excerpts into English).

Code	Description	Occurrences, n	Examples
C1. Chatbot interface design and functionalities	Comments on chatbot graphic interface design, including font-size and text display on screen, chatbot esthetics, and use of button-limited options	4	“Well, I liked having a menu with numbers and that you can just type a number, because I think it makes it much faster.” [P05] “Spacing in the text display is adequate and the text fits almost all the screen, right? It’s not so small that we have to strain our eyes to read it, and it is also easy to scroll the screen up and down to be able to go back to check something.” [P13]
C2. Positive user experience	General positive comments on overall experience of interacting with the chatbot, for example, ease of use	26	“I thought it (the experience) was nice, the bot was very easy to use and you get clear instructions about what you have to do, there is no way you can get lost.” [P12] “It is very good that it is responding very fast. It doesn't have that, you know, delay to answer.” [P03]
C3. Understanding chatbot underlying rationale	Comments on user perception and understanding of rationale behind the chatbot operation	3	“There is an interesting logic underlying the bot. It looks like a flowchart, right? You have a yes or no question, then depending on the answer, you go to another group of questions...” [P01] “...I noticed that depending on the information I submit about my symptoms, it will give me a direction, it will direct me to where to go, isn’t it?” [P15]