My side project uses Firebase, and wow has it come a long way since I first tried it several years ago.
We're building a mobile app. Some of our data is sourced by 3rd party APIs. Since those APIs have limits, we don't want the client to access them directly, as that situation could easily break those limits. So instead, we're going to have a Firebase function (basically an AWS Lambda – which came first?) retrieve data from the API, if and only if that data is not present in our database.
"Serverless", in other words. That is the appealing part about using Firebase – you use their features directly, instead of building them yourself, into your own server. But how will it play out in practice?