In this post to his site Freek Van der Herten shares an Envoy script that can be used to deploy an application to a remote server with (or without I suppose) one key thing: downtime.

Envoy is Laravel’s official task runner. Using a Blade style syntax tasks can be defined that can be run both locally and remotely. At Spatie, we’ve been using Envoy for quite some time to deploy code on production servers. [...] [Our trusty Envoy scriot] had a big downside: the application would be down for close to a minute. This week I took the time to solve that issue.

He talks about the changes he made to their deployment process towards using a symlink-based system as suggested by this guide. The result is an updated script that follows the same flow. He steps through the changes he made to the script and tweaks used to get the best performance out of the deploy process.