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Configuring Outbound Email
Phabricator User Documentation (Configuration)

Instructions for configuring Phabricator to send mail.


Phabricator can send outbound email through several different mail services, including a local mailer or various third-party services. Options include:

Send Mail WithSetupCostInboundNotes
Amazon SESEasyCheapNoRecommended
External SMTPMediumVariesNoGmail, etc.
Local SMTPHardFreeNosendmail, postfix, etc
CustomHardFreeNoWrite a custom mailer for some other service.
Drop in a HoleEasyFreeNoDrops mail in a deep, dark hole.

See below for details on how to select and configure mail delivery for each mailer.

Overall, Postmark and Mailgun are much easier to set up, and using one of them is recommended. Both will also let you set up inbound email easily.

If you have some internal mail service you'd like to use you can also write a custom mailer, but this requires digging into the code.

Phabricator sends mail in the background, so the daemons need to be running for it to be able to deliver mail. You should receive setup warnings if they are not. For more information on using daemons, see Managing Daemons with phd.


Before configuring outbound mail, you should first set up metamta.default-address in Configuration. This determines where mail is sent "From" by default.

If your domain is, set this to something like

Ideally, this should be a valid, deliverable address that doesn't bounce if users accidentally send mail to it.

Configuring Mailers

Configure one or more mailers by listing them in the the cluster.mailers configuration option. Most installs only need to configure one mailer, but you can configure multiple mailers to provide greater availability in the event of a service disruption.

A valid cluster.mailers configuration looks something like this:

    "key": "mycompany-mailgun",
    "type": "mailgun",
    "options": {
      "domain": "",
      "api-key": "..."

The supported keys for each mailer are:

  • key: Required string. A unique name for this mailer.
  • type: Required string. Identifies the type of mailer. See below for options.
  • priority: Optional string. Advanced option which controls load balancing and failover behavior. See below for details.
  • options: Optional map. Additional options for the mailer type.
  • inbound: Optional bool. Use false to prevent this mailer from being used to receive inbound mail.
  • outbound: Optional bool. Use false to prevent this mailer from being used to send outbound mail.
  • media: Optional list<string>. Some mailers support delivering multiple types of messages (like Email and SMS). If you want to configure a mailer to support only a subset of possible message types, list only those message types. Normally, you do not need to configure this. See below for a list of media types.

The type field can be used to select these third-party mailers:

  • mailgun: Use Mailgun.
  • ses: Use Amazon SES.
  • sendgrid: Use SendGrid.
  • postmark: Use Postmark.

It also supports these local mailers:

  • sendmail: Use the local sendmail binary.
  • smtp: Connect directly to an SMTP server.
  • test: Internal mailer for testing. Does not send mail.

You can also write your own mailer by extending PhabricatorMailAdapter.

The media field supports these values:

  • email: Configure this mailer for email.
  • sms: Configure this mailer for SMS.

Once you've selected a mailer, find the corresponding section below for instructions on configuring it.

Setting Complex Configuration

Mailers can not be edited from the web UI. If mailers could be edited from the web UI, it would give an attacker who compromised an administrator account a lot of power: they could redirect mail to a server they control and then intercept mail for any other account, including password reset mail.

For more information about locked configuration options, see Configuration Guide: Locked and Hidden Configuration.

Setting cluster.mailers from the command line using bin/config set can be tricky because of shell escaping. The easiest way to do it is to use the --stdin flag. First, put your desired configuration in a file like this:

    "key": "test-mailer",
    "type": "test"

Then set the value like this:

phabricator/ $ ./bin/config set --stdin cluster.mailers < mailers.json

For alternatives and more information on configuration, see Configuration User Guide: Advanced Configuration

Mailer: Postmark

Postmark is a third-party email delivery service. You can learn more at

To use this mailer, set type to postmark, then configure these options:

  • access-token: Required string. Your Postmark access token.
  • inbound-addresses: Optional list<string>. Address ranges which you will accept inbound Postmark HTTP webook requests from.

The default address list is preconfigured with Postmark's address range, so you generally will not need to set or adjust it.

The option accepts a list of CIDR ranges, like (IPv4) or ::ffff:0:0/96 (IPv6). The default ranges are:


The default address ranges were last updated in January 2019, and were documented at:

Mailer: Mailgun

Mailgun is a third-party email delivery service. You can learn more at Mailgun is easy to configure and works well.

To use this mailer, set type to mailgun, then configure these options:

  • api-key: Required string. Your Mailgun API key.
  • domain: Required string. Your Mailgun domain.

Mailer: Amazon SES

Amazon SES is Amazon's cloud email service. You can learn more at

To use this mailer, set type to ses, then configure these options:

  • access-key: Required string. Your Amazon SES access key.
  • secret-key: Required string. Your Amazon SES secret key.
  • endpoint: Required string. Your Amazon SES endpoint.
NOTE: Amazon SES requires you to verify your "From" address. Configure which "From" address to use by setting metamta.default-address in your config, then follow the Amazon SES verification process to verify it. You won't be able to send email until you do this!

Mailer: SendGrid

SendGrid is a third-party email delivery service. You can learn more at

You can configure SendGrid in two ways: you can send via SMTP or via the REST API. To use SMTP, configure Phabricator to use an smtp mailer.

To use the REST API mailer, set type to sendgrid, then configure these options:

  • api-key: Required string. Your SendGrid API key.

Older versions of the SendGrid API used different sets of credentials, including an "API User". Make sure you're configuring your "API Key".

Mailer: Sendmail

This requires a sendmail binary to be installed on the system. Most MTAs (e.g., sendmail, qmail, postfix) should do this, but your machine may not have one installed by default. For install instructions, consult the documentation for your favorite MTA.

Since you'll be sending the mail yourself, you are subject to things like SPF rules, blackholes, and MTA configuration which are beyond the scope of this document. If you can already send outbound email from the command line or know how to configure it, this option is straightforward. If you have no idea how to do any of this, strongly consider using Postmark or Mailgun instead.

To use this mailer, set type to sendmail. There are no options to configure.

Mailer: SMTP

You can use this adapter to send mail via an external SMTP server, like Gmail.

To use this mailer, set type to smtp, then configure these options:

  • host: Required string. The hostname of your SMTP server.
  • port: Optional int. The port to connect to on your SMTP server.
  • user: Optional string. Username used for authentication.
  • password: Optional string. Password for authentication.
  • protocol: Optional string. Set to tls or ssl if necessary. Use ssl for Gmail.

Disable Mail

To disable mail, just don't configure any mailers.

Testing and Debugging Outbound Email

You can use the bin/mail utility to test, debug, and examine outbound mail. In particular:

phabricator/ $ ./bin/mail list-outbound   # List outbound mail.
phabricator/ $ ./bin/mail show-outbound   # Show details about messages.
phabricator/ $ ./bin/mail send-test       # Send test messages.

Run bin/mail help <command> for more help on using these commands.

You can monitor daemons using the Daemon Console (/daemon/, or click Daemon Console from the homepage).


By default, Phabricator will try each mailer in order: it will try the first mailer first. If that fails (for example, because the service is not available at the moment) it will try the second mailer, and so on.

If you want to load balance between multiple mailers instead of using one as a primary, you can set priority. Phabricator will start with mailers in the highest priority group and go through them randomly, then fall back to the next group.

For example, if you have two SMTP servers and you want to balance requests between them and then fall back to Mailgun if both fail, configure priorities like this:

    "key": "smtp-uswest",
    "type": "smtp",
    "priority": 300,
    "options": "..."
    "key": "smtp-useast",
    "type": "smtp",
    "priority": 300,
    "options": "..."
    "key": "mailgun-fallback",
    "type": "mailgun",
    "options": "..."

Phabricator will start with servers in the highest priority group (the group with the largest priority number). In this example, the highest group is 300, which has the two SMTP servers. They'll be tried in random order first.

If both fail, Phabricator will move on to the next priority group. In this example, there are no other priority groups.

If it still hasn't sent the mail, Phabricator will try servers which are not in any priority group, in the configured order. In this example there is only one such server, so it will try to send via Mailgun.

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