Which should you choose?
Start with Supabase if your application benefits from PostgreSQL, SQL queries and row-level access rules. Consider Firebase Firestore for a document-oriented client workflow with synchronization and offline support. Firebase also offers PostgreSQL through SQL Connect, so choose the specific database product before comparing platforms. Model access rules, query volume and recovery rather than deciding from a free-plan badge.
Editorial judgment based on the official facts below
What the official documentation says
Compare the specific workflow and constraints below before committing to a plan. Each factual entry links to an official source. Our recommendations are separate editorial judgments; we have not measured comparative performance, code quality or the cost of completing the same workload.
Choose around your situation
Start with the scenario closest to the work you need to do. The suggested starting point is an editorial judgment, not a universal winner. Check a small representative task and its failure states before replacing an existing workflow or moving a production application.
A small B2B SaaS has accounts, memberships and SQL reports
Start by evaluating Supabase
Write the relational schema and test tenant access policies with two accounts. Estimate all projects and the compute you need. Firebase SQL Connect may also fit PostgreSQL requirements; compare its operation and SDK workflow instead of assuming the Firebase alternative must be Firestore.
A client app needs document sync and offline interactions
Evaluate Firestore
Model the documents and listeners required for one journey. Confirm offline behavior for the relevant SDK, test Security Rules and count how reconnections affect operations. Denormalization, indexes and reporting requirements can change the maintenance cost of a document model.
Compare the operating bill
Scope: one small SaaS, including development and production environments; no performance benchmark. Supabase charges combine plan, compute and usage, so additional projects matter. Firebase pricing varies by selected service and region; SQL Connect also depends on Cloud SQL and trial conditions. Authentication methods, storage, network egress and recovery features can add costs. Budget alerts are signals, not automatic spending caps.
Questions before committing
Use these questions to identify a missing requirement before subscribing. A documented capability is not proof that it works for your codebase or user workload. Verify the actual project, plan and operating responsibilities with the person who will maintain the result.
Is Firebase only NoSQL?
No. Firestore is document-oriented, while Firebase SQL Connect uses Cloud SQL for PostgreSQL. These have different query, client SDK and billing decisions. Specify the database and workload rather than treating the platform name as a data model.
Can either backend secure my SaaS automatically?
Managed authentication identifies a user; authorization still requires the right rules for each resource. Test anonymous and cross-tenant access, migration failures and recovery using disposable data. This guide is not an audit of your policies or a guarantee of production readiness.
A small next step
Model three related entities and one cross-account denial. Test the busiest query/listener journey, estimate usage for two environments and practice recovery. Choose the data model and operations you can maintain.
Method and sources
Official sources were checked on 2026-10-05. This is public-source research, not a hands-on benchmark. Recommendations and trial checklists are editorial judgments. These ordinary links imply no approved affiliate partnership or commission. Confirm current terms before subscribing; no search ranking, AI citation or product outcome is guaranteed.
Continue choosing your stack
Keep builder, coding and backend choices separate so you can replace one part deliberately. Browse another decision guide when it answers a real question for your product, and use the linked tool profiles for more detailed preparation before evaluating a provider.