server: Create a SMTP server object.

Description

Create an object which can be used to send messages to an SMTP server.

Usage

server(
  host,
  port = 25,
  username = NULL,
  password = NULL,
  insecure = FALSE,
  reuse = TRUE,
  helo = NA,
  protocol = NA,
  use_ssl = NA,
  test = FALSE,
  pause_base = 1,
  max_times = 5,
  ...
)
gmail(username, password, ...)
sendgrid(password, ...)
mailgun(username, password, ...)
sendinblue(username, password, ...)
mailersend(username, password, ...)
mailfence(username, password, ...)
zeptomail(password, ...)
smtpbucket(...)
mailtrap(username, password, sandbox = FALSE, bulk = FALSE, ...)

Value

A function which is used to send messages to the server.

Arguments

host: DNS name or IP address of the SMTP server.
port: Port that the SMTP server is listening on.
username: Username for SMTP server.
password: Password for SMTP server or API key.
insecure: Whether to ignore SSL issues.
reuse: Whether the connection to the SMTP server should be left open for reuse.
helo: The HELO domain name of the sending host. If left as NA then will use local host name.
protocol: Which protocol (SMTP or SMTPS) to use for communicating with the server. Default will choose appropriate protocol based on port.
use_ssl: Whether to use SSL. If not specified then SSL will be used if the port is 465 or 587. This enables SSL on non-standard ports.
test: Test login to server.
pause_base: Base delay (in seconds) for exponential backoff. See rate_backoff.
max_times: Maximum number of times to retry.
...: Additional curl options. See curl::curl_options() for a list of supported options.
sandbox: Use email sandbox to test server.
bulk: Send bulk mail to multiple recipients.

Gmail

If you're having trouble authenticating with Gmail then you should try the following:

enable 2-factor authentication and
create an app password.

Then use the app password rather than your usual account password.

Sendgrid

To use SendGrid you'll need to first create an API key. # nolint Then use the API key as the password.

SendGrid will accept messages on ports 25, 587 and 2525 (using SMTP) as well as 465 (using SMTPS).

Mailgun

To use Mailgun you'll need to first register a sender domain. This will then be assigned a username and password.

Mailgun will accept messages on ports 25 and 587 (using SMTP) as well as 465 (using SMTPS).

Sendinblue

To use Sendinblue you'll need to first create an account. You'll find your SMTP username and password in the SMTP & API section of your account settings.

MailerSend

To use MailerSend you'll need to first create an account. You'll find your SMTP username and password under Domains. See How to send emails via SMTP with MailerSend.

Although this is not likely to be a problem in practice, MailerSend insists that all messages have at minimum a valid subject and either text or HTML content.

Mailfence

To use Mailfence you'll need to create a premium account.

ZeptoMail

Zeptomail is an email sending service provided by Zoho Corporation. It is designed primarily for transactional email delivery, which includes emails like password resets, order confirmations, notifications, and other automated, non-marketing communications that websites and applications need to send to their users.

SMTP Bucket

SMTP Bucket is a fake SMTP server that captures all the messages it receives and makes them available through a website or REST API.

Details

These functions return a function that can then be called with a message object. This function mediates the interaction with the Simple Mail Transfer Protocol (SMTP) server.

SMTP is a plain text protocol, which means that it is not secure. The secure variant, SMTPS, comes in two flavours: TLS and StartTLS. With TLS (also called Implicit TLS) the connection with the server is initiated using an Secure Socket Layer (SSL) or Transport Layer Security (TLS) certificate. Such a connection is secure from the start. By contract, a StartTLS connection is initiated in plain text and then upgraded to TLS if possible. By convention TLS operates on port 465 and StartTLS on port 587.

The specifications of an SMTP server are given in an SMTP URL, which takes one of the following forms:

mail.example.com — hostname only
mail.example.com:587 — hostname and port
smtp://mail.example.com — SMTP URL (default port)
smtps://mail.example.com — SMTPS URL (default port)
smtp://mail.example.com:25 — SMTP URL (explicit port)
smtps://mail.example.com:587 — SMTPS URL (explicit port)

Examples

Run this code

# Set parameters for SMTP server (with username and password).
smtp <- server(
  host = "smtp.gmail.com",
  port = 587,
  username = "bob@gmail.com",
  password = "bd40ef6d4a9413de9c1318a65cbae5d7"
)

# Set parameters for a (fake) testing SMTP server.
#
# More information about this service can be found at https://www.smtpbucket.com/.
#
smtp <- server(
  host = "mail.smtpbucket.com",
  port = 8025
)

# Create a message
msg <- envelope() %>%
  from("bob@gmail.com") %>%
  to("alice@yahoo.com")

# Send message (verbose output from interactions with server)
if (FALSE) {
smtp(msg, verbose = TRUE)
}

# To confirm that the message was sent, go to https://www.smtpbucket.com/ then:
#
# - fill in "bob@gmail.com" for the Sender field and
# - fill in "alice@yahoo.com" for the Recipient field then
# - press the Search button.

# With explicit HELO domain.
#
smtp <- server(
  host = "mail.example.com",
  helo = "client.example.com"
)

# Set parameters for Gmail SMTP server. The host and port are implicit.
smtp <- gmail(
  username = "bob@gmail.com",
  password = "bd40ef6d4a9413de9c1318a65cbae5d7"
)

# Set API key for SendGrid SMTP server.
smtp <- sendgrid(
  password = "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"
)

# Set username and password for Mailgun SMTP server.
smtp <- mailgun(
  username = "postmaster@sandbox9ptce35fdf0b31338dec4284eb7aaa59.mailgun.org",
  password = "44d072e7g2b5f3bf23b2b642da0fe3a7-2ac825a1-a5be680a"
)

# Set username and password for Sendinblue SMTP server.
smtp <- sendinblue(
  username = "bob@gmail.com",
  password = "xsmtpsib-c75cf91323adc53a1747c005447cbc9a893c35888635bb7bef1a624bf773da33"
)

# Set username and password for MailerSend SMTP server.
smtp <- mailersend(
  username = "NS_Pf3ALM@gmail.com",
  password = "e5ATWLlTnWWDaKeE"
)

# Set username and password for Mailfence SMTP server.
smtp <- mailfence(
  username = "bob",
  password = "F!Uosd6xbhSjd%63"
)

# Set password for ZeptoMail SMTP server.
# nolint start
smtp <- zeptomail("yA6KbHsL4l2mmI8Ns0/fs9iSTj8yG0dYBgfIG0j6Fsv4P2uV32xh8ciEYNYlRkgCC7wRfkgWA==")
# nolint end

# SMTP Bucket server.
smtp <- smtpbucket()

# SMTP Bucket server.
smtp <- smtpbucket()

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