As our web applications grow in complexity we often find the need for background processing. Sending email blasts, transforming data sets, and other long-running tasks are not the kinds of things you want to do in a web request. In this article, we cover how to build long-running daemons and how to scale up our backend architectures with concurrency, all using PHP. With a little bit of planning and a queuing system, we can turn linear PHP scripts into multi-processor, multi-server powerhouses.