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There is the JSON RPC 2.0 documentation, which specifies it - but the outdated PDF documentation tells me that batch is not supported.

EDIT: ok, outdated docs tell that batch requests are supported since 1.4...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