Supabase provides a full PostgreSQL database with SQL, table editor, and RLS policies, while Firebase offers NoSQL Firestore and Realtime Database.
Supabase offers a managed PostgreSQL database with built-in table editor, SQL editor, and Row-Level Security. Firebase provides Cloud Firestore (NoSQL document) and Realtime Database (NoSQL). This changes data modeling, querying, and integrity enforcement.
Why it matters: Teams that rely on relational data integrity, complex JOINs, and existing SQL tooling will find Supabase more natural, whereas Firebase suits applications needing flexible, schema-less data storage.