I just finished rewrite of big (400+K LOC) 10 year old pylons codebase to pyramid. We were able to share our models, services and 100% template code, and about

I just finished rewrite of big (400+K LOC) 10 year old pylons codebase to pyramid. We were able to share our models, services and 100% template code, and about 80% of view code was untouched. What you want to do is follow this recipe: https://docs.pylonsproject.org/projects/pyramid-cookbook/en/latest/porting/legacy.html https://docs.pylonsproject.org/projects/pyramid-cookbook/en/... You put a 404 handler in pyramid to delegate not found views to pylons, and move views one by one. In a pyramid tween you can push pyramid session, settings, request,response to pylons app globals. This approach works really well - you don't have to do total rewrite. You have same request/response objects, same sqlalchemy ORM, so you can certainly take advantage of that during migration. I don't think anyone at our company regreted the path we took and it was a massive codebase that was making money - no one can afford rewriting that from scratch in $WHATEVERISCOOL today solution. It certainly is possible - if you need any hints contact me.