opt_expand will indeed get you what you want. However, I should mention that option is no longer officially sanctioned by Asana - they’re discouraging folks from using it and they’d prefer you make the additional calls to get the additional info.
opt_fields and opt_expand are mutually exclusive - you can only use one of the two, and opt_expand is a superset of opt_fields (i.e. it does everything opt_fields does plus it expands sub-objects), so if you’re going to use opt_expand (in spite of my #1 above ), remove the opt_fields.
You have a typo: you’re missing the “t” in your opt_expand.
In the opt_fields parameter, you can use the “dot” to query for subitems fields.
Example, when you query your tasks, instead of “projects” opt_fields, you can use:
opt_fields: ‘name, assignee, projects.name, projects.otherfield, …’
Frederic, this is perfect. Thank you so much for your help. With opt_expand I have to request way more data than what I currently need making the process clunkier