What language was RabbitMQ written in?

I'm looking at the 开发者_运维问答repos and there are so many projects, not sure which are wrappers/clients and which is the actual project.

Is it Erlang?

Yes, it is Erlang. You can check this out by downloading the source for the server here:

http://www.rabbitmq.com/releases/rabbitmq-server/v2.3.1/

See Wikipedia: RabbitMQ

The RabbitMQ server is written in Erlang and is built on the Open Telecom Platform framework for clustering and failover.

The actual documentation/promo on http://rabbitmq.com is rather fluffy ;-)