LavinMQ, an open-source message broker written in Crystal
RabbitMQ alternative in Crystal that runs on a fraction of the hardware.

MQTT on Kafka is interesting, but the login wall hides what makes this different.
IoT engineers, message queue architects
EMQX · Mosquitto · HiveMQ
RabbitMQ alternative in Crystal that runs on a fraction of the hardware.
MQTT broker on a $10 ESP32 kills the Raspberry Pi tax for home automation.
Wire-protocol parsing means zero Docker overhead for Kafka integration tests.
Complete Kafka pipeline demo with live dashboard, but it's a teaching repo not a product.
Removes broker disk complexity entirely—S3 as durable log cuts Kafka ops burden and cost dramatically.
S3-backed Kafka eliminates broker state management; inspired by Warpstream but open-source.