Hosting resources are very solution specific, depending on the average user load that you expect on your portal you should have adequate resources for that load.
At a minimum, we recommend the Azure “Standard S2” tier. The Azure Standard tier provides multiple slots for staging, daily backups, and generally enough power for most portal sites
When your project is put into production, or has higher load requirements, we suggest you scale up the pricing tier or instances to achieve the best performance out of your Portal. We recommend at least “Standard S3” for all production instances.