diff --git a/.env.example b/.env.example
new file mode 100644
index 0000000..39c0887
--- /dev/null
+++ b/.env.example
@@ -0,0 +1,31 @@
+# Application
+APP_BASE_URL=https://evening-detective.crabs-games.art
+FILE_PREFIX_DOMAIN=https://evening-detective-api.crabs-games.art/api/files/
+JWT_SECRET=change-me
+PARTICIPATION_SECRET=change-me
+YANDEX_FORMS_TOKEN=
+GAME_TIMEZONE=Asia/Barnaul
+
+# PostgreSQL
+POSTGRES_DB=evening_detective_server
+POSTGRES_USER=postgres
+POSTGRES_PASSWORD=change-me
+MIGRATIONS_DATABASE_URL=postgresql://postgres:change-me@127.0.0.1:5432/evening_detective_server?sslmode=disable
+TZ=Asia/Barnaul
+PGTZ=Asia/Barnaul
+
+# RustFS / S3
+S3_USER=rustfs
+S3_PASSWORD=change-me
+S3_BUCKET=evening-detective
+
+# SMTP
+SMTP_HOST=mail.crabs-games.art
+SMTP_PORT=465
+SMTP_USER=evening_detective@crabs-games.art
+SMTP_PASSWORD=change-me
+SMTP_REPLY_TO=
+SMTP_TIMEOUT=10s
+
+# Existing server directory containing mail.crabs-games.art TLS certificates.
+REPROXY_SSL_DIR=/srv/reproxy/var/ssl
diff --git a/docker-compose.yml b/docker-compose.yml
index 6b584a9..738b518 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -105,6 +105,40 @@ services:
       retries: 3
       start_period: 30s
 
+  mailserver:
+    image: mailserver/docker-mailserver:15.1.0
+    container_name: mailserver
+    hostname: mail.crabs-games.art
+    ports:
+      - "25:25"
+      - "465:465"
+      - "587:587"
+      - "993:993"
+    environment:
+      SSL_TYPE: manual
+      SSL_DOMAIN: mail.crabs-games.art
+      SSL_CERT_PATH: /etc/letsencrypt/mail.crabs-games.art.crt
+      SSL_KEY_PATH: /etc/letsencrypt/mail.crabs-games.art.key
+      PERMIT_DOCKER: host
+      POSTMASTER_ADDRESS: admin@crabs-games.art
+      ENABLE_SPAMASSASSIN: "1"
+      ENABLE_CLAMAV: "1"
+      ENABLE_FAIL2BAN: "1"
+      POSTFIX_INET_PROTOCOLS: ipv4
+    cap_add:
+      - NET_ADMIN
+    volumes:
+      - mail_data:/var/mail
+      - mail_state:/var/mail-state
+      - mail_logs:/var/log/mail
+      - ${REPROXY_SSL_DIR}/certificates/acme-v02.api.letsencrypt.org-directory/mail.crabs-games.art:/etc/letsencrypt:ro
+    restart: always
+    networks:
+      - crabs-network
+
 volumes:
   postgres_data:
   rustfs_data:
+  mail_data:
+  mail_state:
+  mail_logs: