The Upload API is not rate-limited.
The Admin API is rate-limited. Because Admin API methods can operate on many assets simultaneously or require searching your account's database or search index, the rate of calls is limited for performance and stability reasons.
Cloudinary’s Admin APIs (listing & deleting resources) are limited in default to 500 requests per hour for our Free plan. For our paid plans, the Admin API hourly rate-limit is automatically increased to 2000 calls per hour. The rate-limit can be raised higher for those on an Enterprise plan.