Do I have to specify a 'to' recipient?

Question

When I\'m sending email via mailgun, must I specify a \'to\' recipient?

In some cases, I\'d prefer to specify only \'Bcc\' recipients.

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EDIT

Answer 1

Eventually, the SMTP call is being translated to a call to the SMTP provided which is usually not forced to have a 'to' recipient, but the best way is to perform a test where you send an email with only 'bcc' recipient (you can send it to yourself as a test'