Is kirby the proper WCMS for a high volume website? We are looking for a solution moving away from a typ03 website with integration to ticketing and movie program website. Not many pages but essential integration with a movie program system newsletter and ticketing system.
Hm, your question is a bit general.
Kirby can certainly handle big websites and high visitor traffic, where the latter is probably more a question of the server being able to handle it.
As regards the integrations, Kirby is very open to any kind of integration, so that shouldn’t be a problem at all but might require developing a plugin depending on what sort of system you want to integrate and how it needs to be integrated.