diff --git a/.envrc.sample b/.envrc.sample
index dac0ff9..43b68a1 100644
--- a/.envrc.sample
+++ b/.envrc.sample
@@ -26,3 +26,9 @@ export DB_PASSWORD_VERSION=v1
 
 # Backups
 #export COMPOSE_FILE="compose.yml:compose.backup.yml"
+
+# SMTP
+#export COMPOSE_FILE="compose.yml:compose.mailrelay.yml"
+#export SMTP_HOST="postfix_relay_app"
+#export MSMTP_CONF_VERSION=v1
+#export ENTRYPOINT_MAILRELAY_CONF_VERSION=v1
diff --git a/compose.mailrelay.yml b/compose.mailrelay.yml
new file mode 100644
index 0000000..81725a1
--- /dev/null
+++ b/compose.mailrelay.yml
@@ -0,0 +1,31 @@
+---
+version: "3.8"
+ 
+services:
+  wordpress:
+    entrypoint: /docker-entrypoint2.sh
+    environment:
+      - SMTP_HOST=${SMTP_HOST}
+    networks:
+      - mail
+    configs:
+      - source: entrypoint_mailrelay_conf
+        target: /docker-entrypoint2.sh
+        mode: 0555
+      - source: mstmp_conf
+        target: /etc/msmtprc
+        mode: 0555
+
+networks:
+  mail:
+    external: true
+
+configs:
+  mstmp_conf:
+    name: ${STACK_NAME}_mstmp_conf_${MSMTP_CONF_VERSION}
+    file: msmtp.conf.tmpl
+    template_driver: golang
+  entrypoint_mailrelay_conf:
+    name: ${STACK_NAME}_entrypoint_mailrelay_${ENTRYPOINT_MAILRELAY_CONF_VERSION}
+    file: entrypoint.mailrelay.sh.tmpl
+    template_driver: golang
diff --git a/entrypoint.mailrelay.sh.tmpl b/entrypoint.mailrelay.sh.tmpl
new file mode 100644
index 0000000..e65f652
--- /dev/null
+++ b/entrypoint.mailrelay.sh.tmpl
@@ -0,0 +1,9 @@
+#!/bin/bash
+
+apt-get update && DEBIAN_FRONTEND=noninteractive apt-get install -y msmtp && rm -rf /var/lib/apt/lists/*
+
+echo "sendmail_path = /usr/bin/msmtp -t -i" >> /usr/local/etc/php/conf.d/sendmail.ini
+
+# Upstream ENTRYPOINT
+# https://github.com/docker-library/wordpress/blob/master/php7.4/apache/Dockerfile#L120
+/usr/local/bin/docker-entrypoint.sh apache2-foreground "$@"
diff --git a/msmtp.conf.tmpl b/msmtp.conf.tmpl
new file mode 100644
index 0000000..991a6b9
--- /dev/null
+++ b/msmtp.conf.tmpl
@@ -0,0 +1,3 @@
+account default
+host {{ env "SMTP_HOST" }}
+auto_from on