As a former user of Kafka, this is awesome and it would have been a huge help for our company if this was available then. I'm glad to hear that a company is offering Kafka as opposed to other propriety versions(AWS Kinesis etc).<p>One thing is odd though, there is no mention of disk space at all and only a configuration of retention time. One of Kafka's best features is the use of disk to store large amounts of messages, you are not RAM bound. Heroku seems to only allows you to set retention times? This could be awesome if they are giving you "unlimited" disk space, but could also be a beta oversight. Interested to see how this progresses.