Email SMTP — Input & Output

Output Ports

Port	Trigger Condition	Description
success	SMTP accepted the message	The SMTP server accepted the email for delivery. Note: acceptance by the SMTP server does not guarantee delivery to the recipient's inbox — bounces and spam filtering happen post-acceptance.
error	SMTP connection or send failure	Triggered when the SMTP server refuses the connection, authentication fails, the server returns an error code, or a network timeout occurs. The error details are available in the output object.

Input Fields Available in Expressions

Field	Type	Description
`vars.*`	any	Workflow variables from upstream nodes (e.g. `vars.customer_name`, `vars.invoice_pdf_base64`).
`input.*`	any	Original workflow trigger payload.
`env.*`	string	Environment configuration values such as `env.SUPPORT_EMAIL` or `env.COMPANY_NAME`.
`workflow.id`	string	Unique execution ID for correlation and audit logging.
`now()` / `utcnow()`	datetime	Current timestamp functions usable in subject lines and bodies.

Output Data Schema

Field	Type	Description
`sent`	boolean	`true` when the SMTP server accepted the message. `false` on failure.
`message_id`	string	The SMTP Message-ID header value assigned to the sent email. Useful for audit trails and delivery tracking correlation.
`recipients_accepted`	array	List of email addresses accepted by the SMTP server for delivery.
`recipients_rejected`	array	List of email addresses rejected by the SMTP server (e.g. invalid address format, relay denied). Usually empty for authenticated SMTP.
`send_time_ms`	integer	Time in milliseconds from SMTP connection to server acknowledgment.
`error_code`	string	SMTP error code if sending failed (e.g. `535` for authentication failure, `550` for mailbox unavailable). Empty on success.
`error_message`	string	Human-readable SMTP error description. Empty on success.

Example Output: Successful Send

{
  "sent": true,
  "message_id": "<20251114093211.8a2b3c4d@mail.bizfirst.io>",
  "recipients_accepted": ["jane.smith@customer.com"],
  "recipients_rejected": [],
  "send_time_ms": 412,
  "error_code": "",
  "error_message": ""
}

Example Output: Authentication Failure

{
  "sent": false,
  "message_id": "",
  "recipients_accepted": [],
  "recipients_rejected": [],
  "send_time_ms": 203,
  "error_code": "535",
  "error_message": "Authentication credentials invalid. Please verify the SMTP username and password in your credential configuration."
}

Example Output: Multi-Recipient Send

{
  "sent": true,
  "message_id": "<20251114103540.1e2f3g4h@mail.bizfirst.io>",
  "recipients_accepted": [
    "cfo@company.com",
    "finance@company.com",
    "ops@company.com"
  ],
  "recipients_rejected": [],
  "send_time_ms": 538,
  "error_code": "",
  "error_message": ""
}

Accessing output downstream: Use the node's output in downstream expressions. For example, if the node is named sendConfirmation:
{{ nodes.sendConfirmation.output.message_id }} — The sent message ID
{{ nodes.sendConfirmation.output.sent }} — Boolean success flag