Quillon

Quillon models the whole SaaS as Ash resources: users, organizations, memberships, subscriptions and API keys, each with policies declared next to the data. Ash Authentication provides passwords, magic links and OAuth, AshAdmin gives a back office for free, and a JSON:API and GraphQL endpoint are generated from the same resources. Stripe billing runs through a small Ash extension.

The kit is opinionated about declarative code. Adding a field with validation and permissions is often three lines. It is excellent once Ash clicks. The limitation: Ash has its own learning curve on top of Elixir and Phoenix, and when something misbehaves, the stack traces go through layers of macros that take a while to read.