> I'm curious just how realistic the "internal" behaviour is emulated.

It seems like some reasonable shortcuts are taken, like services reading from each other's states directly instead of using APIs [0]. But then it will go so far as to run an in-process NodeJS emulator for lambda functions, and give it a shim so the code it runs can call other emulated AWS services using the main router [1].

[0] https://app.ilograph.com/demo.ilograph.AWS%2520Emulator/Serv... [1] https://app.ilograph.com/demo.ilograph.AWS%2520Emulator/Invo...