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AgentPost accepts all incoming email addressed to your mailboxes and delivers it instantly to your browser. There is no polling or manual refresh required.

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How mail reaches your mailbox

AgentPost uses a catch-all mechanism at the mail server level. Every message sent to the AgentPost domain (agent.agentpost.email) or to any custom domain you have configured with inbound enabled is accepted by the mail server. The system then looks up the recipient address in your mailboxes and routes the message accordingly. If the recipient address does not match any existing mailbox, the message is silently discarded — no bounce or error is returned to the sender. This is intentional: it prevents information leakage about which addresses exist.
The maximum inbound message size is 25 MB, including all attachments.

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Real-time delivery

When a new message arrives, AgentPost stores it and immediately broadcasts a notification over a private WebSocket channel scoped to your account. Every browser tab you have open receives the update at the same time:
  • The new message appears at the top of your inbox without a page refresh
  • A toast notification shows the subject and sender name
  • The sidebar updates to reflect the new message count
If your browser is not connected (WebSocket unavailable), your messages are still stored safely. They appear the next time you load or refresh the page.

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Multi-recipient handling

When a single email is addressed to more than one of your mailbox addresses — whether in the To, CC, or BCC fields — AgentPost creates a separate message record for each matching mailbox. Each copy is independent: deleting the message in one mailbox does not affect the others. Recipients that do not match any mailbox are skipped silently, and the matching recipients continue to be processed normally.

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Reading your messages

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Message list

The All Messages dashboard and individual mailbox views show messages grouped into conversation threads. Each thread card displays:
  • Subject line (or “No Subject” if absent)
  • Sender name or email address
  • Relative timestamp (e.g., “today”, “2 days ago”)
  • A 200-character preview of the message body, stripped of HTML tags
  • On the dashboard, a badge identifying which mailbox received the message
Click Load more at the bottom of the list to page through older threads (50 per page).

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Message content

If the message includes an HTML part, AgentPost renders it in a sandboxed iframe. The sandbox prevents script execution, blocks external resource loads that could track you, and isolates the message’s styles from the rest of the page UI. Use the HTML tab in the message view to see the rendered version.
When a message contains only a plain text part — or when you prefer to read without formatting — switch to the Text tab. The content is displayed in a preformatted block that preserves line breaks and spacing. If neither an HTML nor a plain text part is available, the view shows “No content available.”
When a message includes attachments, they appear in a grid between the message header and the body content. Each attachment shows its filename, file size, and a MIME-type icon. Image attachments display a small inline thumbnail. Click Download to save any attachment to your device.Non-image attachments are available for download only — inline preview is not supported for documents, PDFs, or other binary formats.
Replies to messages are grouped into conversation threads. When you open a multi-message thread, all messages appear in chronological order. Older messages are collapsed to show just the sender and a one-line preview; the latest message is expanded by default. Click any collapsed message to expand it.If your mailbox is on a custom domain, a reply composer appears at the bottom of the thread so you can respond without leaving the page.

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Message header details

Every message view shows:
  • Subject, From, To, CC, BCC
  • Date and time in your browser’s local timezone, with a relative label in parentheses (e.g., 3/12/2026, 10:30:14 PM (today))
  • An expandable Message Details section with the RFC Message-ID and received timestamp