Brokerless Messaging
A messaging approach in which endpoints communicate without a separate broker, leaving more of the queueing, reconnection, delivery and failure contract to the application.
Removing the broker does not remove messaging semantics. Queue placement, reconnect behaviour, slow-consumer handling, message lifetime and processing acknowledgement still need an explicit contract.
With NetMQ and ZeroMQ-style transports, those decisions become visible in the socket pattern and application protocol. PUB/SUB, REQ/REP, and ROUTER/DEALER do not provide the same delivery guarantees, and a high-water mark is normally an in-memory backpressure boundary rather than durable queue storage.
The applied side is covered in Brokerless Messaging with NetMQ, where socket ownership, poller design, reconnect behaviour and idempotency are treated as one reliability problem.