Problem

While importing a Swagger JSON or YAML API specification, this popup error is encountered:

"Unable to determine resource type"

Resolution

First, determine the size of the swagger file/API spec. If it is larger than about 3MB this is probably the cause of the issue. The recommendation in this case is to break the large API into smaller chunks.

If the swagger file is smaller than 3MB, then it's possible that the API spec references a mime-type that's not configured in Policy Studio > Server Settings. The solution here is to open the configuration in Policy Studio, go to Server Settings > General > Mime and add the "unknown" mime-type(s), then deploy the change.