Mandrill

Send transactional emails via Mandrill API with templates and attachments

Overview

The Mandrill tool sends transactional emails through the Mandrill API (Mailchimp Transactional Email). It supports two operations: (1) sendHtml — send an email with raw HTML content, and (2) sendTemplate — send an email using a pre-defined Mandrill template with merge variable substitution. Both operations support binary file attachments from upstream items. Supports tracking, metadata, merge variables, scheduling, subaccounts, Google Analytics integration, and custom email headers.

Category: Communication
Tool Name: mandrill
Version: 1

Appearance: Icon: lucide-Mail | Color: #FFD94C

Node Type

Action (Binary) — handles file/binary data operations

Input / Output

Direction	Port(s)
Input	Input
Output	Output, Error

Credentials

This tool requires Mandrill API credentials. See the Credentials Guide for setup instructions.

Resources

Resource	Value
Message	message

Operations

Operation	Value	Description
Send Template	sendTemplate	Send message based on a Mandrill template
Send HTML	sendHtml	Send message based on raw HTML content

Parameters

Send HTML takes no parameters of its own — see All Operations, and put the body in Options → HTML.

Message: Send Template

Parameter	Type	Required	Default	Description
Template	string	Yes	—	The template slug to use. Find template slugs in the Mandrill dashboard under Outbound > Templates. Supports expressions.

All Operations

Parameter	Type	Required	Default	Description
From Email	string	Yes	—	Email address of the sender, optionally with name: “Name <email>”. Supports expressions.
To Email	string	Yes	—	Email address of the recipient. Multiple addresses can be separated by commas. Supports expressions like {{ $json.email }}.
JSON Parameters	boolean	No	false	Whether to provide merge vars, metadata, headers, and attachments as raw JSON strings instead of UI fields.
Options	collection	No	{}	The message body plus every delivery, tracking and content setting.
— Async	boolean	No	false	Whether to enable background sending mode optimized for bulk sending. Messages with more than 10 recipients are always sent asynchronously.
— Auto Text	boolean	No	false	Whether to automatically generate a text part for messages that are not given text.
— Auto HTML	boolean	No	false	Whether to automatically generate an HTML part for messages that are not given HTML.
— BCC Address	string	No	—	An optional address to receive an exact copy of each recipient’s email. Supports expressions.
— From Name	string	No	—	Optional from name to be used. Supports expressions.
— Google Analytics Campaign	string	No	—	Value to set for the utm_campaign tracking parameter. If not provided the email’s from address will be used.
— Google Analytics Domains	string	No	—	Comma-separated domains for which matching URLs will have Google Analytics parameters appended automatically.
— HTML	string	No	—	The HTML content of the email. Supports expressions.
— Important	boolean	No	false	Whether this message is important and should be delivered ahead of non-important messages.
— Inline CSS	boolean	No	false	Whether to automatically inline all CSS styles in the HTML. Only for HTML documents less than 256KB.
— IP Pool	string	No	—	The name of the dedicated IP pool to use. If not set or pool does not exist, the default pool is used.
— Preserve Recipients	boolean	No	false	Whether to expose all recipients in the To header for each email.
— Return Path Domain	string	No	—	A custom domain to use for the message’s return-path.
— Send At	dateTime	No	—	Scheduled send time as UTC timestamp (YYYY-MM-DD HH:MM:SS). Past times send immediately. Additional fee applies.
— Signing Domain	string	No	—	A custom domain to use for SPF/DKIM signing instead of mandrill.
— Subaccount	string	No	—	The unique ID of a subaccount for this message. Must already exist or will fail with an error.
— Subject	string	No	—	Subject line of the email. Supports expressions.
— Tags	string	No	—	Comma-separated tags for the message. Max 100 unique tags, max 50 chars each. Tags starting with ”_” are reserved.
— Text	string	No	—	The plain text content of the email. Supports expressions.
— Track Clicks	boolean	No	false	Whether to turn on click tracking for the message.
— Track Opens	boolean	No	false	Whether to turn on open tracking for the message.
— Tracking Domain	string	No	—	A custom domain to use for tracking opens and clicks instead of mandrillapp.com.
— URL Strip QS	boolean	No	false	Whether to strip the query string from URLs when aggregating tracked URL data.
— View Content Link	boolean	No	false	Whether to remove content logging for sensitive emails.
Merge Vars (mergeVarsJson)	json	No	—	Global merge variables as a JSON array of {name, content} objects. (shown when JSON Parameters is true)
Metadata (metadataJson)	json	No	—	Metadata as a JSON object of key-value pairs. Up to 10 fields are searchable via Mandrill search API. (shown when JSON Parameters is true)
Attachments (attachmentsJson)	json	No	—	Attachments as a JSON array of {type, name, content} objects where content is base64-encoded. (shown when JSON Parameters is true)
Headers (headersJson)	json	No	—	Custom email headers as a JSON object. Most headers are allowed. (shown when JSON Parameters is true)
Merge Vars (mergeVarsUi)	fixedCollection	No	{}	Global merge variables for template substitution. (shown when JSON Parameters is false)
— Name	string	No	—	Merge variable name (e.g., FNAME).
— Content	string	No	—	Merge variable content value. Supports expressions.
Metadata (metadataUi)	fixedCollection	No	{}	Custom metadata key-value pairs. Up to 10 fields are searchable via Mandrill search API. (shown when JSON Parameters is false)
— Name	string	No	—	Metadata key name.
— Value	string	No	—	Metadata value. Supports expressions.
Attachments (attachmentsUi)	fixedCollection	No	{}	File attachments. Add manual base64 attachments or reference binary properties from upstream nodes. (shown when JSON Parameters is false)
— MIME Type	string	No	—	The MIME type of the attachment. Part of a Manual Attachment entry.
— File Name	string	No	—	The file name of the attachment. Part of a Manual Attachment entry.
— Content (Base64)	string	No	—	The content of the attachment as a base64-encoded string. Part of a Manual Attachment entry.
— Binary Property	string	No	data	Name of the binary property containing data to attach to the email. Part of a Binary Attachment entry.
Headers (headersUi)	fixedCollection	No	{}	Custom email headers (most headers are allowed). (shown when JSON Parameters is false)
— Name	string	No	—	Header name (e.g., Reply-To).
— Value	string	No	—	Header value. Supports expressions.
Max Concurrency	number	No	10	Maximum number of items to process concurrently.

Output Data

One email per input item and one output item per input item — this node never fans out, even when To Email lists several recipients. The Mandrill result is written to mandrillResponse on the output item; the rest of the item JSON passes through unchanged and binary data is forwarded.

{
  "mandrillResponse": []
}

mandrillResponse holds Mandrill’s send result exactly as returned — an array with one entry per recipient the message was addressed to. Address a single recipient’s result as {{ $json.mandrillResponse[0] }}, and use a Split Out node on mandrillResponse if you want one workflow item per recipient.

Attachments. Two routes reach the same place: name an upstream binary property in an Attachments → Binary Attachment entry, or supply base64 content yourself in a Manual Attachment entry (or in Attachments as JSON when JSON Parameters is on).

Usage Examples

• Send an HTML email with a PDF attachment via Mandrill
• Send a template-based email with merge variables
• Send bulk transactional emails with tracking enabled
• Send email with binary file attachments from upstream nodes
• Send a scheduled email for later delivery

Example Configuration

Send an HTML email — note that the body lives in Options:

{
  "type": "mandrill",
  "parameters": {
    "resource": "message",
    "operation": "sendHtml",
    "fromEmail": "sender@example.com",
    "toEmail": "recipient@example.com",
    "jsonParameters": false,
    "options": {
      "subject": "Welcome to Our Service",
      "html": "<h1>Welcome!</h1><p>Thank you for joining us.</p>",
      "text": "Welcome! Thank you for joining us.",
      "fromName": "Welcome Team",
      "trackOpens": true,
      "trackClicks": true
    }
  }
}

Send a template email with merge variables and metadata entered as UI fields:

{
  "type": "mandrill",
  "parameters": {
    "resource": "message",
    "operation": "sendTemplate",
    "template": "welcome-template",
    "fromEmail": "Welcome Team <welcome@example.com>",
    "toEmail": "{{ $json.email }}",
    "jsonParameters": false,
    "options": {
      "subject": "Welcome {{ $json.firstName }}!",
      "fromName": "Customer Success",
      "trackOpens": true,
      "important": true,
      "tags": "welcome,onboarding"
    },
    "mergeVarsUi": {
      "mergeVarsValues": [
        {
          "name": "FNAME",
          "content": "{{ $json.firstName }}"
        },
        {
          "name": "COMPANY",
          "content": "{{ $json.company }}"
        }
      ]
    },
    "metadataUi": {
      "metadataValues": [
        {
          "name": "user_id",
          "value": "{{ $json.userId }}"
        },
        {
          "name": "signup_source",
          "value": "website"
        }
      ]
    }
  }
}

Send an email with an attachment, with merge vars, attachments and headers supplied as JSON:

{
  "type": "mandrill",
  "parameters": {
    "resource": "message",
    "operation": "sendHtml",
    "fromEmail": "orders@example.com",
    "toEmail": "customer@example.com",
    "jsonParameters": true,
    "options": {
      "subject": "Your Order Invoice #12345",
      "html": "<h1>Order Complete</h1><p>Please find your invoice attached.</p>",
      "fromName": "Order Processing",
      "trackOpens": true
    },
    "mergeVarsJson": "[{\"name\": \"ORDER_ID\", \"content\": \"12345\"}, {\"name\": \"TOTAL\", \"content\": \"$149.99\"}]",
    "attachmentsJson": "[{\"type\": \"application/pdf\", \"name\": \"invoice-12345.pdf\", \"content\": \"JVBERi0xLjQKJcOkw7zDtsOuw6A\"}]",
    "headersJson": "{\"Reply-To\": \"support@example.com\", \"X-Order-ID\": \"12345\"}"
  }
}

Scheduled email with custom tracking:

{
  "type": "mandrill",
  "parameters": {
    "resource": "message",
    "operation": "sendTemplate",
    "template": "monthly-report",
    "fromEmail": "reports@example.com",
    "toEmail": "admin@example.com,manager@example.com",
    "jsonParameters": false,
    "options": {
      "subject": "Monthly Performance Report",
      "sendAt": "2024-12-01T09:00:00Z",
      "trackOpens": true,
      "trackClicks": true,
      "trackingDomain": "tracking.example.com",
      "tags": "reports,monthly,automated",
      "preserveRecipients": false,
      "important": true
    },
    "mergeVarsUi": {
      "mergeVarsValues": [
        {
          "name": "MONTH",
          "content": "November 2024"
        },
        {
          "name": "REVENUE",
          "content": "$45,230"
        }
      ]
    }
  }
}

Attach a file that an upstream node downloaded, without touching base64:

{
  "type": "mandrill",
  "parameters": {
    "resource": "message",
    "operation": "sendHtml",
    "fromEmail": "reports@example.com",
    "toEmail": "{{ $json.email }}",
    "jsonParameters": false,
    "options": {
      "subject": "Your report is ready",
      "html": "<p>The report is attached.</p>"
    },
    "attachmentsUi": {
      "attachmentsBinary": [
        {
          "property": "data"
        }
      ]
    }
  }
}

Error Handling

Mode	Behavior
stop	Halts workflow on first error
continue	Skips failed items, passes successful ones through
errorPort	Routes failed items to Error output port

Tips

Send transactional emails via Mandrill API with templates, HTML, merge variables, and binary attachments.

Key Notes

• The body lives in Options. There is no top-level HTML or Subject field — open Options and add HTML, Text and Subject there, for both operations.
• JSON Parameters switches the whole panel. With it off you get the four UI builders (Merge Vars, Metadata, Attachments, Headers); with it on you get the four raw-JSON fields instead. The two sets never appear together, so pick one style per node.
• Braces belong to the workflow, not to Mandrill. Anything you type as {{ … }} is evaluated as a workflow expression before Mandrill sees it, and only $json, $index, $itemCount, $datetime and $uuid are understood. Personalise from item data with {{ $json.firstName }}, and pass template placeholders through Merge Vars rather than writing them into the subject or body.
• Template Send needs a slug, not a name. Copy it from Outbound > Templates in the Mandrill dashboard.
• Send At is a paid extra on Mandrill, and a timestamp in the past sends straight away.