Mixin Messenger is built on the Signal protocol by end-to-end encryption. Only the sender and receiver know what you are talking about, the transmission process is encrypted, and the server and service provider (Mixin) CAN NOT check the messages.
How do I know the messages are encrypted?
The end-to-end encryption protects the messages in private and group chats by default.
The messages in bots (starting with Mixin id 7000xxxxxx) do not follow the E2EE protocol by default. Some bots switch on the E2EE protection; some are not. So please check the status of the messages that which messages are marked with a lock 🔒 are encrypted.