For every reservation, Booking.com provides both you and the guest with a unique and anonymous alias email address. All messages sent to this alias email address will be forwarded to the guest, including links, images and attachments (up to 15 MB).
It’s not our standard policy to share guest’s private email addresses with accommodation partners. This helps to protect information against spam, viruses, and third-party misconduct.
We use an automated system to check for malicious content like spam. This also limits the sending of certain file types, such as zip, .rar, and .exe.
Visit "Does Booking.com have access to the messages I send to guests?" to read how Booking.com accesses communication sent through Booking.com.