Inboxes are currently in private beta and only available to a limited
number of users. The response shape might change before GA.Get early access if you’re interested in testing this feature.Once you have access, upgrade your Resend SDK to use the new methods:
npm install resend@6.28.1-preview-inboxes.2
npm install -g resend-cli@2.22.0-preview-inboxes.2
source is always system, because the email pipeline sends this event, even when the API or an agent sent the email.
{
"type": "inbox.thread.created",
"created_at": "2026-09-29T12:00:00.000Z",
"data": {
"source": "system",
"inbox_id": "b3e2b2b6-3f0e-4c8e-9ad3-2f43a1e2c7f1",
"thread_id": "7c1f0a2e-5d3b-4e8a-9f61-2b8d4c6e1a90",
"email_id": "4ef9a417-02e9-4d39-ad75-9611e0fcc33c",
"thread": {
"object": "inbox_thread",
"id": "7c1f0a2e-5d3b-4e8a-9f61-2b8d4c6e1a90",
"subject": "Question about my invoice",
"folder": "inbox",
"labels": [],
"read": false
},
"email": {
"id": "4ef9a417-02e9-4d39-ad75-9611e0fcc33c",
"direction": "inbound",
"from": "Steve Wozniak <steve.wozniak@gmail.com>",
"to": ["support@example.com"],
"cc": [],
"bcc": [],
"reply_to": [],
"subject": "Question about my invoice",
"message_id": "<CAF7c1f0a2e5d3b@mail.gmail.com>",
"attachments": [
{
"id": "2a0c9ce0-3112-4728-976e-47ddcd16a318",
"filename": "invoice.pdf",
"size": 48213
}
],
"read": false,
"received_at": "2026-09-29T12:00:00.000Z"
}
}
}