SparkPost transport for Symfony Mailer Installation composer require gam6itko/sparkpost-mailer Configuration services.yaml services: mailer.transport_factory.sparkpost: class: Gam6itko\Symfony\Mailer\SparkPost\Transport\SparkPostTransportFactory arguments: ['@event_dispatcher', '@?http_client', '@?monolog.logger'] tags: - {name: mailer.transport_factory} .env Default region MAILER_DSN=sparkpost+api://api_key@default MAILER_DSN=sparkpost+smtp://user:password@default:port EU region MAILER_DSN=sparkpost+api://api_key@default?region=eu MAILER_DSN=sparkpost+smtp://user:password@default:port?region=eu Tests Using sink server About sink server services: Gam6itko\Symfony\Mailer\SparkPost\EventListener\SinkEnvelopeListener: tags: ['kernel.event_subscriber'] Also Sparkpost's "transmissions" API reference