Yes, it is possible to connect Voiceflow to WhatsApp and control the conversation flow. Voiceflow provides a Dialog API that allows you to interact with the Voiceflow agent and control the conversation from WhatsApp. This includes the ability to stop the conversation whenever the client wants.
To achieve this, you would need to integrate the Voiceflow agent with the WhatsApp Business API. This integration allows you to render buttons on WhatsApp and receive voice messages. You can use the PicoVoice Speech to Text service to convert voice messages received on WhatsApp into text that can be processed by the Voiceflow agent.
As for your question about device compatibility, the integration should work on any device that supports WhatsApp, including both PCs and mobile phones. The WhatsApp Business API is platform-independent, meaning it can be used on any device that can run WhatsApp.
Remember, the Voiceflow agent is powered by the data you add. You can create a 'Chat' or 'Voice' agent and add data sources like PDFs, URLs, Text files to your agent. The more documents you upload, the better the answers your agent can provide.
In terms of controlling the conversation flow, Voiceflow provides a feature called 'Custom Actions'. This feature allows your Voiceflow application to stop at a Custom Action step and wait for the client application (in this case, WhatsApp) to send back an event. This can be used to control when the conversation continues or stops.
Please note that while I've provided a high-level overview, the actual implementation would require some technical knowledge and familiarity with APIs and coding. You can find more detailed information and instructions in the Voiceflow documentation.