Design a Backend-as-a-Service on Postgres

Problem Design Supabase's platform: a backend-as-a-service over Postgres providing auto-generated APIs, auth, storage, and realtime.

Functional requirements

• Auto-generate REST/GraphQL from the schema.
• Auth (JWT) plus row-level security.
• Realtime change subscriptions.
• File storage.

Non-functional requirements

• Many projects, each with its own Postgres.
• Secure multi-tenant isolation.
• Realtime at scale.

Areas to go deep

• Per-project Postgres provisioning and isolation.
• The auto-API layer and how RLS enforces authorization.
• Realtime via logical replication fan-out; auth/JWT policy model; storage + CDN.