Feature Flags v Environment Variables

At first glace, Feature Flags and Environment Variables might seem like they are similar, but as we’ll see, they fulfill vastly different roles and conflating the two can be problematic.

To choose between the two

Feature Flags

Toggle behavior on the fly
Independent of environment

Environment Variables

If need to decide during app startup
More rigid between environments

Issue I had… I was starting Apollo Server

If it’s a configuration you are passing to a service that is starting, then remote FF may not work. For example, I thought, “Let me have a FF toggle to turn GraphQL introspection on/off on the server”.

Problems.

This value cannot be dynamically changed, would take a server restart to pick up a new value.
This value is needed immediately on boot up. While using Unleash, the remote connection to the server was not yet initialized when the Apollo server needed the configuration.

Photo by Vladislav Klapin on Unsplash