AMQP 1.0, standardized as ISO/IEC 19464, defines a binary wire protocol for exchanging messages between applications with explicit acknowledgment, flow control and settlement rules, so senders and receivers can agree on exactly which messages were delivered. Brokers such as RabbitMQ and Apache ActiveMQ and cloud services such as Azure IoT Hub and Service Bus speak it.
Compared with MQTT, AMQP is heavier but richer: it carries structured metadata, supports multiple message queue patterns beyond publish-subscribe and works well for backend services that need guaranteed, ordered processing of device events. Few constrained devices use it directly; the common pattern is MQTT or HTTPS from the device to a cloud broker, then AMQP from the broker into enterprise systems. Choosing it on a microcontroller usually means paying for features the device cannot exploit.
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