ap2i/config/packages/mercure.yaml

mercure:
    hubs:
        default:
            url: '%env(MERCURE_URL)%'
            public_url: '%env(MERCURE_PUBLIC_URL)%'
            jwt:
                secret: '%env(MERCURE_PUBLISHER_JWT_KEY)%'
                algorithm: 'hmac.sha256'
                publish: ['*']

#            jwt_provider: App\Mercure\JWTProvider