An Exchange Online delegate permission under which messages look as though the mailbox or group itself sent them, with nothing revealing who actually did. Send on Behalf is the alternative that shows the delegate.
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Terms in this definition
- Exchange Online
Microsoft 365's hosted service for mail, calendars and contacts. Defender for Office 365 protects these mailboxes.
- Agents (classic) API
First-generation Foundry Agent Service API, based on threads, messages and runs. It is deprecated, replaced by conversations and responses, and retires on 31 March 2027.
- Send on Behalf
An Exchange Online delegate permission under which recipients see that the delegate sent the message for the mailbox owner. Send As, by contrast, conceals the delegate entirely.
Related terms
- Full Access
A permission in Exchange Online that allows a delegate to open another person's mailbox and read, create or delete items in it. It does not allow sending messages as or for the owner; that requires Send As or Send on Behalf.
- Shared mailbox
An Exchange Online mailbox owned by no single person, such as a team's info address. Several people get Full Access to read it and send from it using Send As or Send on Behalf.