I have an external app that I would like to use to create records of a custom object through the rest API. I can create Accounts just fine, but have not been able to replicate that functionality for any custom object.

I took a look at workbench.developerforce.com, and found that the rest explorer is not returning information about any custom objects.

I am logged in as a system administrator, so I should have access to everything. What am I doing wrong?