Send email

Use the curl SMTP client to send an email. The message argument must be properly formatted RFC2822 email message with From/To/Subject headers and CRLF line breaks.

send_mail(
  mail_from,
  mail_rcpt,
  message,
  smtp_server = "smtp://localhost",
  use_ssl = c("try", "no", "force"),
  verbose = TRUE,
  ...
)

Arguments

mail_from	email address of the sender.
mail_rcpt	one or more recipient email addresses. Do not include names, these go into the message headers.
message	either a string or connection with (properly formatted) email message, including sender/recipient/subject headers. See example.
smtp_server	hostname or address of the SMTP server, or, an smtp:// or smtps:// URL. See "Specifying the server, port, and protocol" below.
use_ssl	Request to upgrade the connection to SSL using the STARTTLS command, see CURLOPT_USE_SSL for details. Default will try to SSL, proceed as normal otherwise.
verbose	print output
...	other options passed to handle_setopt. In most cases you will need to set a username and password to authenticate with the SMTP server.

Specifying the server, port, and protocol

The smtp_server argument takes a hostname, or an SMTP URL:

• mail.example.com - hostname only

• mail.example.com:587 - hostname and port

• smtp://mail.example.com - protocol and hostname

• smtp://mail.example.com:587 - full SMTP URL

• smtps://mail.example.com:465 - full SMTPS URL

By default, the port will be 25, unless smtps:// is specified--then the default will be 465 instead.

Encrypting connections via SMTPS or STARTTLS

There are two different ways in which SMTP can be encrypted: SMTPS servers run on a port which only accepts encrypted connections, similar to HTTPS. Alternatively, a regular insecure smtp connection can be "upgraded" to a secure TLS connection using the STARTTLS command. It is important to know which method your server expects.

If your smtp server listens on port 465, then use a smtps://hostname:465 URL. The SMTPS protocol guarantees that TLS will be used to protect all communications from the start.

If your email server listens on port 25 or 587, use an smtp:// URL in combination with the use_ssl parameter to control if the connection should be upgraded with STARTTLS. The default value "try" will opportunistically try to upgrade to a secure connection if the server supports it, and proceed as normal otherwise.

Examples

# Set sender and recipients (email addresses only)
recipients <- readline("Enter your email address to receive test: ")
#> Enter your email address to receive test: 
sender <- '[email protected]'

# Full email message in RFC2822 format
message <- 'From: "R (curl package)" <[email protected]>
To: "Roger Recipient" <[email protected]>
Subject: Hello R user!

Dear R user,

I am sending this email using curl.'

# Send the email
send_mail(sender, recipients, message, smtp_server = 'smtps://smtp.gmail.com',
  username = 'curlpackage', password  = 'qyyjddvphjsrbnlm')
#> Error in curl_fetch_memory(smtp_server, handle = h): RCPT failed: 555