To speed up delivery globally, WhatsApp uses "edge" servers. If you are in London and your friend is in Tokyo, the CDN ensures the file is stored on a server physically closer to the recipient.
curl -v "https://chat.cdn.whatsapp.net/v1/media/..." \ -H "User-Agent: WhatsApp/2.24.1.85" chat.cdn.whatsapp.net
To the uninitiated, "chat.cdn.whatsapp.net" looks like a random string of characters. However, breaking it down reveals its specific function. To speed up delivery globally, WhatsApp uses "edge" servers
To understand the subdomain, let’s parse it from right to left: To speed up delivery globally