Incremental refresh Rest Api best practice

Thanks for your input. I've have been working the issue quite a bit. The main issue was, the slow speed, when doing the bulk import for 4 years, since the api is call for every single day. The API support a from and to date, which is able to minimize the ammount of data. I did make a big mistake, when call the api. The result was, that I imported  all data (4 years) for every single date, which made it very slow. Performance has imporved, but I need to test if the problem has been solved.