[twunde]

For webapps you would use a reverse proxy such as nginx or haproxy and replace your application page by page. Then configure the reverse proxy to send all requests to /home to go to the new stack and all other requests go to the old stack. Then flip the switch for every page you finish converting. For backend work, it's similar. You can have an api built in a new stack and it can just have a different endpoint or use a reverse proxy. Backend workers can pick up work from a different queue or you can switch the old job worker off and turn on the new one, and then monitor that everything is working as planned. The really important thing about the strangler pattern is that you need some easy way to turn on bits of functionality while turning off the corresponding old parts. It can be feature flags, it can be routing middleware. You can rip out the guts of the angular routing mechanism and use that to flip the switch.

[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.