What is the format of inbound email webhooks?

Inbound emails are processed based on the routes you've set up, and messages matching the routes are sent to your specified URL(s) as a webhook. The webhooks generally follow the same format as other webhooks for Transactional Email.

The webhook request is a standard POST request with a single parameter: mandrill_events. This parameter contains a JSON-encoded array of the messages that match the webhook information.

Key	Description
ts	The timestamp when the event occurred—integer UTC Unix format.
event	The name of the event (for inbound, will be inbound).
msg	Details about the message for which the event occurred.
	raw_msg	the full content of the received message, including headers and content
	headers	an array of the headers received for the message, such as ‘Dkim-Signature’, ‘Mime-version’, ‘Date’, ‘Message-Id’, etc.
	text	the text version of the message
	html	the HTML version of the message
	from_email	the from email address for the message
	from_name	the from name for the message
	to	the recipients of the message, and their names
	email	the email address where Transactional Email received the message
	subject	the subject line of the message
	tags	the tags applied to the message
	sender	the Transactional Email sender of the message
	attachments	an array of attachments for the message, with filenames as keys. If there are no attachments, key is omitted. Each attachment has the following keys:
		name	the file name
		type	the MIME type of the attachment
		content	the attachment content
		base64	boolean whether the attachment contents are Base64 encoded
	images	an array of images for the message, with filenames as keys. If there are no images, key is omitted. Each image has the following keys:
		name	the file name
		type	the MIME type of the image
		content	the image content
	spam_report	the results of processing the message with the default SpamAssassin rules. Contains the following keys:
		score	the total spam score for the message
		matched_rules	an array containing details about the rules that the message matched. Each rule entry contains the following keys:
			name	the name of the rule
			description	a short description of the rule
			score	the score for this individual rule
			spf	spf validation results, or null if an error occurred while checking SPF for the message. Contains the following keys:
				result	the spf validation result. One of: pass, neutral, fail, softfail, temperror, permerror, none
				detail	a human-readable description of the result
			dkim	details about the message’s DKIM signature, if any
				signed	boolean whether the message contained a DKIM signature (true or false)
				valid	whether the message’s DKIM signature was valid. Always false if signed is false.

For inbound emails, tags and sender are included to match other webhooks, but inbound messages generally won’t have tags since they're being received instead of sent, and the sender is null since the event is for a message not being sent by Transactional Email.