Can we use Firebase remote config for feature management on the backend? Is it recommended?

I am trying to add feature toggle/management in my NodeJS backend deployed on AWS Lambda.There were many feature management services like Unleash and LaunchDarkly but I found firebase was cheapest of them all. But in my opinion firebase remote config is for mobile and web apps (basically frontend), so is it recommended to use it on backend as well and that too in serverless environment? firebase-admin do have remote-config related functions but I think those are for controlling those features from your own backend and not other-way around.

I have tried some open source libraries and my other alternative is creating feature management services myself. I don't need A/B testing, user segregation or features available to a group of users and not for others. I need a simple feature on/off toggle which would affect all the users of the system and that can be done using feature flags in the db but after a bunch of features it would be hard to manage.

As you've discovered Firebase Remote Config has client-side SDKs (that consume the remote value) for Android, iOS and Web only. Its server-side SDKs/APIs allow you to set the remote values, but not consume them. So Firebase Remote Config probably won't fit your use-case.