Django

PostgreSQL

settings.py

import os

DATABASES = {
    "default": {
        "ENGINE": "django.db.backends.postgresql",
        "HOST": "pg-7f3k.us-east.databasezy.com",
        "PORT": 5432,
        "NAME": "app",
        "USER": "app",
        "PASSWORD": os.environ["ZB_PASSWORD"],
        "CONN_MAX_AGE": 300,          # persistent connections per worker
        "CONN_HEALTH_CHECKS": True,   # survive free-tier sleeps and rotations
        "OPTIONS": {
            "sslmode": "verify-full",
            "sslrootcert": os.environ.get("ZB_CA", "databasezy-ca.pem"),
        },
    }
}

MySQL

settings.py

import os

DATABASES = {
    "default": {
        "ENGINE": "django.db.backends.mysql",
        "HOST": "mysql-7f3k.us-east.databasezy.com",
        "PORT": 3306,
        "NAME": "app",
        "USER": "app",
        "PASSWORD": os.environ["ZB_PASSWORD"],
        "CONN_MAX_AGE": 300,
        "CONN_HEALTH_CHECKS": True,
        "OPTIONS": {
            "charset": "utf8mb4",
            "ssl": {"ca": os.environ.get("ZB_CA", "databasezy-ca.pem")},
            "ssl_mode": "VERIFY_IDENTITY",
        },
    }
}

Cache and sessions on Valkey

settings.py

CACHES = {
    "default": {
        "BACKEND": "django.core.cache.backends.redis.RedisCache",
        "LOCATION": "rediss://app:%s@valkey-7f3k.us-east.databasezy.com:6379/0" % os.environ["ZB_VALKEY_PASSWORD"],
        "OPTIONS": {"ssl_cert_reqs": "required", "ssl_ca_certs": os.environ.get("ZB_CA", "databasezy-ca.pem")},
    }
}
SESSION_ENGINE = "django.contrib.sessions.backends.cache"

Migrations

python manage.py migrate --noinput in the release step (Kubernetes Job, Render preDeployCommand, Fly release_command). Keep CONN_MAX_AGE × workers under the size’s max_connections; with gunicorn --workers 4 --threads 2 that is up to 8 connections per replica.