When you build a new feature, orchestrating the actual launch schedule between the Product, Engineering, and Marketing teams can be challenging.

While it seems easy to launch something new, a poorly executed rollout can end up being your worst nightmare.

In this article, I will present to you how to use the Go module go-feature-flag to roll out your new features smoothly and help you be confident during the rollout phase. If you are not familiar with the concept of feature flags or feature toggles, I encourage you to read this article by Martin Fowler.

go-feature-flag is a Go module to easily manage your flags. You can refer to this article I wrote a few months ago to understand how it works.

I absolutely don’t think human/manual QA gates should be involved in between the writing of code and its being live. To avoid breaking things every time and to have an early cutoff system, you should use feature flags.

There are a lot of systems available on the market to manage your flags, like LaunchDarkly or UNLEASH, that have Golang support — but this option is expensive, and you have to host a server somewhere to manage your flags.

From this starting point, I came up with the idea to create a simple library with only one file in the back end. This file can be stored in different places (AWS S3, GitHub, an HTTP endpoint somewhere, etc.). This is the only thing you have to host — all the decision logic stands inside the Go module.