At the moment, Baluu does not have a built-in feature to email all customers at once. You can currently email attendees directly from a specific booking.
However, there is a simple workaround you can use.
You can export your full customer list and email them externally using your own email provider (e.g. Gmail, Outlook, Mailchimp, etc.).
Log in to your dashboard.
Go to People.
Select Customers.
In the top-right corner, click More.

Click Export All.
This will download a file containing your full customer list, including:
Names
Email addresses
Phone numbers
Open the exported file.
Copy the email addresses.
Paste them into your email provider.
Compose and send your message.
⚠️ Important:
When sending to multiple customers, always use BCC (Blind Carbon Copy) to protect customer privacy.