A chatbot is a software application used to automate interactions and conversations with people via messaging platforms, including request routing, customer service, and information gathering. Serverless architecture is a design pattern where applications are broken up into individual functions that can be invoked and scaled separately. A serverless WhatsApp chatbot using Python, Google Cloud Functions, and Twilio can be built by creating an HTTP cloud function with a webhook that processes incoming messages from WhatsApp, retrieves country data from the REST Countries public API, and returns human-readable responses to users. The chatbot can handle errors well and can be deployed on the Google Cloud Platform for production use. Alternative architectures include using AWS Lambda or Azure Functions, or building a traditional endpoint using a Python web framework like Flask.