I want to test my SharePoint Framework web part in Office 365, in SharePoint Online.
Therefore I upload the .sppkg file to the App Catalog. Unfortunately SharePoint says my app package is invalid:
Here is a similar question about invalid app packages where the answers say you need a developer tenant for it to work.
But what is a developer tenant? Is there a formal documentation describing the differences of a developer tenant compared to a "normal" one? I thought a dev tenant is just a "normal" one with first release features activated and maybe a pre-created developer site. Am I mistaken?
=== ADDITION ===
If there is a developer tenant subscription available I am more than willing to buy one. It just mustn't expire after x month. I need it to be like a normal tenant. Any hints on how to get such a tenant (and a comparison to "normal" tenants) are welcome.