Hand a message to the engine over HTTP verifiedWritten by the Hub
The HTTP door into the sending queue: the body is a delivery job, the same JSON that would be published to the broker.
In detail
The endpoint takes the delivery job described in the messages chapter and puts it where the engine will find it. Everything that works in a job published to RabbitMQ works here — addresses, tags, attempt ceilings, per-message DKIM — because it is the same object taking a different road. It answers 200 with an empty body. There is no message id in the reply, which means the only way to correlate a submission with its result is to put an identifier into the job yourself; the engine returns custom properties untouched, so a campaign id or a warm-up plan number survives the round trip. For Hub the choice between this and publishing straight to the broker is not about capability but about coupling. The broker is the engine's real interface and needs no token; this needs a token but speaks HTTP, which is easier from a worker that already has an HTTP client. For a warm-up sender on the same network as the node, the broker is the shorter path.