BirdyChat has become the first European chat app to be interoperable with WhatsApp, allowing users to exchange messages with WhatsApp users in the European Economic Area. This is made possible by the Digital Markets Act, which mandates WhatsApp to provide an interface for third-party apps. The feature will be rolled out gradually, and users will need to opt-in to receive messages from third-party apps. This interoperability allows BirdyChat users to start chats with WhatsApp users using their phone number and send messages, photos, and files over an encrypted connection.