Safe AWS Lambda Durable Functions with XState

Photo by Heather McKean on Unsplash Define typesafe workflows running as AWS Lambda Durable Functions using XState Code is available in this repository Background One of the most exciting announcements made during last re:Invent, at least for the serverless enthusiasts, was the introduction of Lambda Durable Functions. At first glance, it appeared to me that Durable Functions might be a nice option for relatively simple workflows. If you need to define a complex workflow, you would probably lean towards AWS Step Functions, which allow creating full-blown state machines. Problem I am somehow biased when it comes to type safety in programming. I really appreciate the help from a compiler, and I feel much safer when the illegal state is unrepresentable. That is one of the reasons I like to use AWS Step Functions. If the flow is created as a state machine, all possible transitions are strictly defined. Your business logic will never end up in a state that is not described in the state mach