Environment Variables¶

Complete reference for every environment variable used by Mailyte, grouped by category.

All variables are set in your .env file at the project root or passed directly through docker-compose.yml. Required variables have no default — the server won't start without them.

Database¶

Variable	Description	Default	Required
`DB_HOST`	MySQL server hostname	—	Yes
`DB_USER`	MySQL username	—	Yes
`DB_PASSWORD`	MySQL password	—	Yes
`DB_NAME`	Database name	`mailserver`	No

[!WARNING] Never commit DB_PASSWORD to version control. Use Docker secrets or a .env file that's in your .gitignore.

Server Identity¶

Variable	Description	Default	Required
`HOSTNAME`	Fully qualified hostname for the mail server	—	Yes
`DOMAIN`	Primary domain for this mail server instance	—	Yes

The HOSTNAME should match your server's reverse DNS (PTR record). A typical value is mail.yourdomain.com. The DOMAIN is the part after the @ in email addresses — usually yourdomain.com.

SSL / TLS¶

Variable	Description	Default	Required
`SSL_CERT_PATH`	Path to the SSL certificate file inside the container	—	Yes
`SSL_KEY_PATH`	Path to the SSL private key file inside the container	—	Yes
`ACME_EMAIL`	Email address for Let's Encrypt registration and renewal notices	—	Yes

[!TIP] If you're using the built-in cert-manager container, certificates land at /etc/letsencrypt/live/$HOSTNAME/. Set your paths accordingly:
Text Only
SSL_CERT_PATH=/etc/letsencrypt/live/mail.yourdomain.com/fullchain.pem
SSL_KEY_PATH=/etc/letsencrypt/live/mail.yourdomain.com/privkey.pem

Redis¶

Variable	Description	Default	Required
`REDIS_HOST`	Redis server hostname	`redis`	No
`REDIS_PORT`	Redis server port	`6379`	No

Redis is used by Rspamd for Bayesian statistics and by the API for rate limiting and caching. The defaults work out of the box if you're using the bundled Redis container.

Postfix¶

Variable	Description	Default	Required
`POSTFIX_MESSAGE_SIZE_LIMIT`	Maximum email size in bytes	`52428800` (50 MB)	No

The default 50 MB limit is generous for most setups. If your users send large attachments regularly, bump it up. Keep in mind that base64 encoding increases attachment size by about 33%, so a 50 MB limit actually caps raw attachments at roughly 37 MB.

Cloud Provider¶

Variable	Description	Default	Required
`CLOUD_PROVIDER`	Cloud platform: `aws` or `azure`	—	No
`AWS_S3_BUCKET`	S3 bucket name for backups and large attachment storage	—	Only if `CLOUD_PROVIDER=aws`

[!NOTE] When CLOUD_PROVIDER is set, Mailyte uses platform-specific features like S3 for attachment offloading. Leave it unset if you're running on bare metal or a provider without special integration.

Tracking¶

Variable	Description	Default	Required
`TRACKING_ENABLED`	Enable open/click tracking	`false`	No
`TRACKING_DOMAIN`	Domain used for tracking pixel and redirect URLs	—	Only if tracking is enabled

When tracking is enabled, Postfix pipes outgoing mail through a tracking filter that rewrites links and injects a tracking pixel. The TRACKING_DOMAIN should point to your API server.

Webhooks¶

Variable	Description	Default	Required
`WEBHOOK_SECRET`	Shared secret for signing webhook payloads (HMAC-SHA256)	—	No
`WEBHOOK_URLS`	Comma-separated list of URLs to receive event notifications	—	No

Webhook events include delivery confirmations, bounces, spam complaints, and tracking events. The secret is used to sign payloads so your endpoint can verify they came from Mailyte.

API Server¶

Variable	Description	Default	Required
`API_HOST`	Host the FastAPI server binds to	`0.0.0.0`	No
`API_PORT`	Port the FastAPI server listens on	`5000`	No

The API server handles domain management, mailbox provisioning, and webhook delivery. In production, put it behind a reverse proxy and don't expose port 5000 directly to the internet.

Example `.env` File¶

Bash

# Database
DB_HOST=mysql
DB_USER=mailyte
DB_PASSWORD=your-secure-password-here
DB_NAME=mailserver

# Server identity
HOSTNAME=mail.yourdomain.com
DOMAIN=yourdomain.com

# SSL
SSL_CERT_PATH=/etc/letsencrypt/live/mail.yourdomain.com/fullchain.pem
SSL_KEY_PATH=/etc/letsencrypt/live/mail.yourdomain.com/privkey.pem
ACME_EMAIL=admin@yourdomain.com

# Redis
REDIS_HOST=redis
REDIS_PORT=6379

# Postfix
POSTFIX_MESSAGE_SIZE_LIMIT=52428800

# Cloud (optional)
# CLOUD_PROVIDER=aws
# AWS_S3_BUCKET=mailyte-backups

# Tracking (optional)
# TRACKING_ENABLED=true
# TRACKING_DOMAIN=track.yourdomain.com

# Webhooks (optional)
# WEBHOOK_SECRET=your-webhook-secret
# WEBHOOK_URLS=https://app.yourdomain.com/webhooks/mail

# API
API_HOST=0.0.0.0
API_PORT=5000

[!WARNING] This is a template. Replace all placeholder values before starting the server. The .env file should have 600 permissions and be owned by root or the Docker user.