I'm trying to implement a record-triggered flow that will post the json for both the prior and current records (IOW, json-serialized versions of {!$Record__Prior} and {!$Record}) to a http endpoint. I can make a text formula and refer to individual fields like {!$Record__Prior.Id} but I don't see a method for json serialization. Would I need to make an Apex class with an invocable method that accepted List<Sobject>, pass the old and new records, and it would generate the json string and return it, then use that to make the http post call? Or is there a simpler method? Goal is just to get the old and new values sent to an http endpoint, if there's a different method available that can do the same easier, that would work too. Outbound messages would have sufficed but they don't seem to include the Record__Prior values.
You create single array with JSON with prior and record values
Paste the above JSON into the callout setup wizard , and it creates a apex class with collection, check if this works.
