diff --git a/.env.docker b/.env.docker
index 20f4436f77..502b81ef49 100644
--- a/.env.docker
+++ b/.env.docker
@@ -50,6 +50,7 @@ COOKIE_DOMAIN=
 COOKIE_SECURE=false
 
 # If you want Firefly III to mail you, update these settings
+# For instructions, see: https://firefly-iii.readthedocs.io/en/latest/installation/mail.html
 MAIL_DRIVER=${MAIL_DRIVER}
 MAIL_HOST=${MAIL_HOST}
 MAIL_PORT=${MAIL_PORT}
@@ -58,6 +59,12 @@ MAIL_USERNAME=${MAIL_USERNAME}
 MAIL_PASSWORD=${MAIL_PASSWORD}
 MAIL_ENCRYPTION=${MAIL_ENCRYPTION}
 
+# Other mail drivers:
+MAILGUN_DOMAIN=${MAILGUN_DOMAIN}
+MAILGUN_SECRET=${MAILGUN_SECRET}
+MANDRILL_SECRET=${MANDRILL_SECRET}
+SPARKPOST_SECRET=${SPARKPOST_SECRET}
+
 # Firefly III can send you the following messages
 SEND_REGISTRATION_MAIL=true
 SEND_ERROR_MESSAGE=false
diff --git a/.env.example b/.env.example
index e45753a2ca..73afaf0470 100644
--- a/.env.example
+++ b/.env.example
@@ -54,6 +54,7 @@ COOKIE_DOMAIN=
 COOKIE_SECURE=false
 
 # If you want Firefly III to mail you, update these settings
+# For instructions, see: https://firefly-iii.readthedocs.io/en/latest/installation/mail.html
 MAIL_DRIVER=log
 MAIL_HOST=smtp.mailtrap.io
 MAIL_PORT=2525
@@ -62,6 +63,12 @@ MAIL_USERNAME=null
 MAIL_PASSWORD=null
 MAIL_ENCRYPTION=null
 
+# Other mail drivers:
+MAILGUN_DOMAIN=
+MAILGUN_SECRET=
+MANDRILL_SECRET=
+SPARKPOST_SECRET=
+
 # Firefly III can send you the following messages
 SEND_REGISTRATION_MAIL=true
 SEND_ERROR_MESSAGE=true
@@ -100,3 +107,5 @@ IS_DOCKER=false
 IS_SANDSTORM=false
 BUNQ_USE_SANDBOX=false
 IS_HEROKU=false
+MAILGUN_DOMAIN=
+MAILGUN_SECRET=
diff --git a/.env.heroku b/.env.heroku
index 91e273659a..55237bd98b 100644
--- a/.env.heroku
+++ b/.env.heroku
@@ -54,6 +54,7 @@ COOKIE_DOMAIN=
 COOKIE_SECURE=false
 
 # If you want Firefly III to mail you, update these settings
+# For instructions, see: https://firefly-iii.readthedocs.io/en/latest/installation/mail.html
 MAIL_DRIVER=log
 MAIL_HOST=smtp.mailtrap.io
 MAIL_PORT=2525
@@ -62,6 +63,12 @@ MAIL_USERNAME=null
 MAIL_PASSWORD=null
 MAIL_ENCRYPTION=null
 
+# Other mail drivers:
+MAILGUN_DOMAIN=
+MAILGUN_SECRET=
+MANDRILL_SECRET=
+SPARKPOST_SECRET=
+
 # Firefly III can send you the following messages
 SEND_REGISTRATION_MAIL=true
 SEND_ERROR_MESSAGE=true
@@ -100,3 +107,5 @@ IS_DOCKER=false
 IS_SANDSTORM=false
 BUNQ_USE_SANDBOX=false
 IS_HEROKU=true
+MAILGUN_DOMAIN=
+MAILGUN_SECRET=
diff --git a/.env.sandstorm b/.env.sandstorm
index c72676704c..5895f63467 100755
--- a/.env.sandstorm
+++ b/.env.sandstorm
@@ -54,6 +54,7 @@ COOKIE_DOMAIN=
 COOKIE_SECURE=false
 
 # If you want Firefly III to mail you, update these settings
+# For instructions, see: https://firefly-iii.readthedocs.io/en/latest/installation/mail.html
 MAIL_DRIVER=log
 MAIL_HOST=smtp.mailtrap.io
 MAIL_PORT=2525
@@ -62,6 +63,12 @@ MAIL_USERNAME=null
 MAIL_PASSWORD=null
 MAIL_ENCRYPTION=null
 
+# Other mail drivers:
+MAILGUN_DOMAIN=
+MAILGUN_SECRET=
+MANDRILL_SECRET=
+SPARKPOST_SECRET=
+
 # Firefly III can send you the following messages
 SEND_REGISTRATION_MAIL=true
 SEND_ERROR_MESSAGE=true
@@ -100,3 +107,5 @@ IS_DOCKER=false
 IS_SANDSTORM=true
 BUNQ_USE_SANDBOX=false
 IS_HEROKU=false
+MAILGUN_DOMAIN=
+MAILGUN_SECRET=
diff --git a/.env.testing b/.env.testing
index 943ab13502..6eec082239 100644
--- a/.env.testing
+++ b/.env.testing
@@ -49,6 +49,7 @@ COOKIE_DOMAIN=
 COOKIE_SECURE=false
 
 # If you want Firefly III to mail you, update these settings
+# For instructions, see: https://firefly-iii.readthedocs.io/en/latest/installation/mail.html
 MAIL_DRIVER=log
 MAIL_HOST=smtp.mailtrap.io
 MAIL_PORT=2525
@@ -57,9 +58,11 @@ MAIL_USERNAME=null
 MAIL_PASSWORD=null
 MAIL_ENCRYPTION=null
 
-# Firefly III can send you the following messages
-SEND_REGISTRATION_MAIL=true
-SEND_ERROR_MESSAGE=false
+# Other mail drivers:
+MAILGUN_DOMAIN=
+MAILGUN_SECRET=
+MANDRILL_SECRET=
+SPARKPOST_SECRET=
 
 
 # Set a Mapbox API key here (see mapbox.com) so there might be a map available at various places.
@@ -96,3 +99,5 @@ IS_DOCKER=false
 IS_SANDSTORM=false
 BUNQ_USE_SANDBOX=true
 IS_HEROKU=false
+MAILGUN_DOMAIN=
+MAILGUN_SECRET=
diff --git a/config/services.php b/config/services.php
index 01c5a3d90e..d72eea32f3 100644
--- a/config/services.php
+++ b/config/services.php
@@ -51,10 +51,12 @@ return [
         'secret' => env('SPARKPOST_SECRET'),
     ],
 
-    'stripe' => [
+    'stripe'   => [
         'model'  => FireflyIII\User::class,
         'key'    => env('STRIPE_KEY'),
         'secret' => env('STRIPE_SECRET'),
     ],
-
+    'mandrill' => [
+        'secret' => env('MANDRILL_SECRET'),
+    ],
 ];