Is batch processing supported with V2 directly (without using the SDKs)? I can't find any discussion of this in the documentation.
No. Without devkit, batch process is not possible. Batch support is present in V2 but it sends each request separately. For Ex - for 10 objects, there will be 10 different transactions(IO).
Just fyi - Actual batch operation support is available in V3. For ex - 10 objects can be created(or any other CRUD operations), using only 1 transaction.
.net devkit - https://developer.intuit.com/docs/0025_quickbooksapi/0055_devkits/0201_ipp_java_devkit_3.0
Thanks