Route Filters

Route filters are expressions that decide when an action is triggered. A filter is created based on the recipient of the incoming email, the headers in the incoming email or use a catch-all filter. Filters support regular expressions in the pattern to give you a lot of flexibility when creating them.

Match Recipient(pattern)

Matches the SMTP recipient of the incoming message against the regular expression pattern. For example, this filter will match messages going to foo@bar.com:

match_recipient("foo@bar.com")

You can use Python-style regular expressions in your filter. For example, this will match all messages coming to any recipient at @bar.com:

match_recipient(".*@bar.com")

Another example, handling plus addressing for a specific recipient:

match_recipient("^chris\+(.*)@example.com$")

Mailgun supports regexp captures in filters, which allows you to use captured values inside of your actions. The example below captures the local name (the part of email before @) and passes it as a mailbox parameter to an application URL:

route filter : match_recipient("(.*)@bar.com")
route action : forward("http://myhost.com/post/?mailbox=\1")

You can use named captures as well:

route filter : match_recipient("(?P<user>.*?)@(?P<domain>.*)")
route action : forward("http://mycallback.com/domains/\g<domain>/users/\g<user>")

Match Header(header,pattern)

This is similar to match-recipient, only instead of looking at a message recipient, it applies the pattern to an arbitrary MIME header for the message.

The example below matches any message with a word "support" in its subject:

match_header("subject", ".*support")

The example below matches any message against several keywords:

match_header('subject', '(.*)(urgent|help|asap)(.*)')

The example below will match any messages deemed spam (if spam filtering is enabled):

match_header('X-Mailgun-Sflag', 'Yes')

match_recipient(pattern) AND match_header(header, pattern)

The example below will match any recipient for a domain, then match if the message is in English:

match_recipient('^(.*)@example.com$') and match_header("Content-Language", "^(.*)en-US(.*)$")

catch_all()

Will create matches if no proceeding routes matched. Usually, you need to use it in a route with a lowest priority, to make sure it evaluates last.