[Spark-Lumen] Compatibility

Compatible in what way? I wouldn't have thought you could install Spark into a Lumen app, given that Spark has a fairly opinionated frontend and Lumen is designed for building APIs.

No. Spark installs Laravel then spark. Spark requires auth and middlewares among others that lumen doesn't ship with.

Plus I think it's beyond the intended use of lumen. Could you make it work? Yes, but at the end of the day you'll have 95% of Laravel installed and a huge amount of time wasted.

Yeah could definitely be setup some way. Make an API on the Lumen side and just send details to that from Spark.

I just need an authentication guard / driver for Lumen that works with https://spark.laravel.com/docs/1.0/api (instead of an api_token in the users table)