The COUNTER 5 Title Master Report and Platform Master Report and their Standard Views are available for SpringerLink and nature.com activity from January 2019 onwards. The Database Master Report will be available in 2021. Our plan is to not supply Item Master Reports..
Springer Nature Librarian Portal: TSV; Via SUSHI: JSON.
There are no limitations. Be aware though, that the files can get quite big if you add several months.
Our plan is to make it possible to create custom views/reports of our Master Reports later this year. You will be able to filter based on attributes and for some attributes, you will be able to choose the level of detail your report should include.