[wink]

Seconded. Took part in a moderately big rewrite with this strategy and it worked pretty well.

Identify key components and subsystems and rewrite them one by one. From the outside you seem to be switching over one REST endpoint after the other, but of course internally it's a bit more difficult, but applications often enough have enough parts that are not SO intertwined that you can do stuff like this. It's a bit related to how you break up a monolith. Find bigger, less coupled parts and shave them off and just touch the glue code.