Thank you for the reply! This sounds much better

While I wanted to ask again about this batch requests, I did some additionaly research...

The only mentioning of batch request that I found in the i-doit documentation is in the "Tips and Tricks" section - the API documentation (1, 2, 3, 4) does not contain a single word.

There is the JSON RPC 2.0 documentation, which specifies it - but the outdated PDF documentation tells me that batch is not supported.

EDIT: ok, outdated docs tell that batch requests are supported since 1.4...

Would be cool to get more information on that topic directly in the docs - because if you really want to do something useful with your API IMO this information is absolutely required. Otherwise you'll waste a lot of time with HTTP requests. And JSON RPC 2.0 is not that well known, that you can assume everybody knows that before. It is neither SOAP nor REST

Nevertheless - thanks for pointing me in the proper direction! I'll try this now.

I already figured out step one and two. But I stumble upon the third one.

Is there a way to receive all category related data for an object in one API request? Currently I need to do ~30 requests per object (because there are that many categories attached to it) which performs quite poor when fetching 400 records.

12000 HTTP requests for reading the data related to 400 objects is a lot IMO. Is there something I am missing or is this currently not supported? (i-doit 1.11)