This article explains how to use Vonage's SMS API with Azure Functions and Node.js to send and receive SMS messages. The author starts by setting up a Vonage account, installing the required libraries, and creating an Azure Function App. They then create a Webhook function that receives incoming SMS messages from Vonage and logs them to the console. To test this functionality, the author sets up a Vonage phone number, deploys the Azure Function App, and sends an SMS message using the Vonage Node.js SDK. The response is converted into emojis, demonstrating how to send a response back to the original sender.