It really wouldn't be that bad - at least not any worse than any other migration of a massively complex project from one platform to another. We deliberately ke

It really wouldn't be that bad - at least not any worse than any other migration of a massively complex project from one platform to another. We deliberately kept our implementation flexible enough to be able to move off Lambda if necessary. Our entire stack can be containerized using Docker. All database interactions are behind interfaces that allow us to swap DB implementations if needed (even to relational ones). All custom CW metric publishing is centralized in a single object that can just as easily publish somewhere else. All our APIs are defined using Swagger which is portable to lots of tooling. The worst part would be replacing IAM with whatever networking/permission model the other platform had, but even that could be approached programmatically to reduce the difficulty. Edit: We also broke the stack into a number of independent microservices, each with their own API, DB, and dedicated CI pipeline. This would allow us to incrementally migrate chunks in parallel without disrupting the entire service.