Fedify: an ActivityPub server framework
The next version of #Fedify, v1.0, adds ParallelMessageQueue, which makes it easy to parallelize sending and receiving activities without increasing the number of processes or nodes.
It's available for preview in v1.0.0-dev.408+f4e245b4 (JSR & npm).
https://unstable.fedify.dev/manual/mq#parallel-message-processing