Hi Factory
Did you get any answers on your slowness concerns?
We are in the same boat - performance of the MYOB API seems completely inconsistent. Even for the most basic requests, it can take anywhere from 100ms to 30 seconds+ to respond. Initially I thought we must be doing something wrong as surely the API couldn't be that bad - but we have confirmed using Postman that it does actually seem to be that bad!
Similar to yourself, we have had no such issues integrating with other accounting software like Xero - their API is great.
We are only using the "Open Access" API level at this stage, I'm wondering if the paid API (Developer Partner / Premium Developer Partner) offers any better performance.
Were you able to get any answers? This just isn't workable for us if this is as good as it gets.