Faster Server Startup in Meteor 3.4 with Deferrables

As you might have seen in the 3.4 release blog post , Meteor has received a HUGE update with a lot of focus on the developer experience. One of the new additions was the new deferrable functions, which we will dive into today in this blog post. Why were those functions added? While seeing teams update to 3.4, we saw a recurring problem: build times have gotten faster with rspack, but the developers were not feeling it because they had a bottleneck at the startup With that in mind, we did our investigation, and we saw that those apps that were not feeling this increase in productivity were the ones that had async or costly operations being done at the startup. You can think of requesting data from external APIs, waiting for sidekick services to get started, etc. For production, this makes sense — you don’t want your app to start without those dependencies ready. You might not need all that. With that in mind, we made this addition to our api. New API The added functions were: deferrable