Emails with bcc addresses

Hello: Is there an app or some method to find out who was on a bcc in an email?
Thank you, Tori

Simply, no.

The whole point of bcc (for old folks, blind carbon copy; for young ones, blind complementary copy) is that the recipients cannot who was bcc’ed.


Nope…that’s what BCC is intended for…unless there’s some secret code to figure it out that I don’t know about.

There’s not. At a high level, sending email works by the sending client telling a server to send email to some addresses, then handing it the entire email, headers and all. There doesn’t need to be any relation between the addresses the server is told to deliver the email to and what’s in the email.

For example, a server could be told to deliver an email to,, and The email it’s given to deliver has a To: header of and a Cc: header of a is the primary recipient, b is a cc recipient, and has been bcc’d, because the server sent them a copy of the email, but doesn’t appear anywhere in the email itself.

For a more technical explanation, the process of sending an email is known as an SMTP conversation. Here’s a fairly good description: The SMTP Transaction. The RCPT TO:<receiver@address> commands tell the server where to deliver the email to, then the text following the DATA command is the email itself, headers and all. A BCC is achieved by including the BCC address in a RCPT TO command, but not in the email headers. As recipients only see the email headers and body and not the SMTP conversation, there’s no way to tell who was BCC’d.

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Thank you. Thought so. Nothing ventured, nothing gained.

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You can find out by some other observation. (OPSEC mistake?)

For example, I received an email from person A. A small list of people were addressed (“To:”).
Later I received an email from person B, not a member of the “To:” list, which quoted the email from A, including its addressees.

I suspect that person B was on “Bcc:” for the first email.
:slightly_smiling_face: :person_shrugging:t2:

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Or it was forwarded to them…

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Sure, there are a lot of out-of-band ways that may work for a specific email—the sender may mention it in the body of the email, a bcc’d address may reply (although as Tommy says, they could have been forwarded the message as well), a bcc’d person may mention it at lunch… But those only work in certain cases and with the cooperation of someone on the email. I read the original question as about a general way that works for any email, and for that, the answer’s still no.

A sysadmin for could manually figure out who in was on a BCC list for a specific email by cross-matching time and subject line [I’ve been involved in that activity one time to find out who in the organization received a defamatory email], but that’s a corner case, and not what I suspect the OP was asking, being the recipient, can this be determined.

All true from the point of view of a receiver of an email.
If the scenario were, how would sender check the BCC list for one of their sent emails (er, …did I send person D a blind copy of that?), the resolution might be: the copy of the email in the Sent folder shows all addressees, including the BCCs.