Symfony configuration

Four places, distinguished by what makes the value change.

Environment variables

Infrastructure only — hosts, credentials, DSNs. Defaults live in .env, which is committed. Real values live in .env.local, which is not. Read them with %env(...)%.

Application behaviour does not belong here.

Parameters

Behaviour that differs per environment. Prefix everything with app. so it can never collide with a parameter from Symfony or a bundle.

# config/services.yaml
parameters:
    app.notifications_email: 'noreply@example.com'
    app.items_per_page: 10

Class constants

Domain values that are intrinsic to the code rather than to a deployment. They work in Twig, in Doctrine queries and in plain PHP without going through the container.

final class Post
{
    public const ITEMS_PER_PAGE = 10;
    public const STATUS_DRAFT = 'draft';
}

Secrets

symfony console secrets:set DATABASE_PASSWORD

The vault is encrypted and safe to commit. Each environment has its own.