End-to-end encrypted messaging ensures only sender and recipient can read messages.
Most email is not end-to-end encrypted by default. Gmail, Outlook, and similar services use TLS to protect email in transit — meaning the connection is encrypted but Google and Microsoft can read your messages on their servers. This is transport encryption, not end-to-end encryption.
Messaging apps that offer genuine end-to-end encryption include Signal (default E2EE for all messages), WhatsApp (E2EE for personal chats, though metadata is visible to Meta), and iMessage between Apple devices over iMessage (not SMS). Standard SMS text messages are not encrypted and are readable by mobile carriers.
Even with end-to-end encrypted messaging, metadata is often visible: the service knows who is communicating with whom, when, how frequently, and from what device and location. This metadata can be highly revealing — knowing that you communicate with a specific doctor or lawyer is sensitive regardless of message content.
iCloud backups of iMessages are not end-to-end encrypted by default — Apple holds the encryption key. This means law enforcement requests can access them. Enable Advanced Data Protection in iOS settings to enable E2EE backups if this matters to you.