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When you reply to an inbound message, AgentPost pre-fills the compose dialog and threads the reply correctly using standard email headers. Like composing from scratch, replies require a custom domain mailbox to send from.

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Reply flow

1

Open a received message

Navigate to any inbound message in your mailbox.
2

Click Reply

Click the Reply button. The compose dialog opens pre-filled with:
  • To — the original sender’s email address
  • Subject — the original subject prefixed with Re:
  • In-Reply-To — the Message-ID of the original message (set automatically for email client threading)
3

Select a From address

Choose which custom domain mailbox to reply from using the From dropdown. Only mailboxes on domains that can currently send (status active or pending_warmup) are listed.
4

Edit the recipients or subject (optional)

Adjust the To field, or expand CC / BCC to add copied recipients. Edit the subject if needed.
5

Write your reply

Enter your message in the body field.
6

Attach files (optional)

Select files using the attachment button. Files upload immediately and are held as drafts until you send. The same limits apply as when composing: 25 MB per file, 25 MB total per message.
7

Send

Click Send. AgentPost creates an outbound Message record linked to the original conversation thread, then delivers the reply.

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Threading

Replies use the standard RFC In-Reply-To email header so the recipient’s email client displays the conversation in thread order. AgentPost groups the reply into the same conversation thread as the original message, keeping the full back-and-forth visible in your mailbox.