From what I've read in documentation, I think you need a sandbox tester to verify in-app purchases, but I think that requires external testing, and I wanted to stay internal for now and not submitting for review. Is it the only way?
Also I'm confused about in-app purchases being submitted for review. I have created one, but the option to submit for review is disabled, so will I be able to test it with sandbox user & external testflight?
Thanks in advance.