Hey - LocalStack founder here. Thanks for the feedback.

We're currently investing some time and resources on refactoring the code base to improve the performance. We have some improvements in the pipeline which we should be able to roll out within the next 1-2 weeks.

Performance (as well as general UX) is definitely high up on our priority list, and we'll continue to invest heavily in this area. Stay tuned!

Happy for any additional suggestions and questions you may have.

Is it the startup time or the overall performance during runtime?

Yes I use localstack a lot and it's very nice but VERY slow and I can't really understand why.