Supabase vs Firebase for a SaaS in 2026

Supabase vs Firebase comes down to the database. Supabase gives every project a Postgres database guarded by row-level security; Firebase centres on Firestore, a NoSQL document store guarded by Security Rules. For a multi-tenant B2B SaaS with teams, roles and billing, Supabase usually fits better. Firebase wins for offline-first mobile apps and teams already on Google Cloud.

The facts below come from each vendor's docs and pricing pages as of October 2026. This blog belongs to shipanysaas, a starter kit built on Supabase, so weigh our conclusion with that in mind. We have tried to give Firebase its due, and there are cases where it is the better pick.

Supabase vs Firebase at a glance

What is the difference between Supabase and Firebase?

The difference is the data model. Supabase is a Postgres database with auth, storage, functions and realtime built around it; Firebase is a set of Google services built around Firestore, a document database. Security, pricing and portability all follow from that.

In Supabase, an invoice is a row in an invoices table with an account_id that points at accounts. You join tables in SQL, and the database enforces foreign keys and constraints. In Firestore, as its data model docs put it, "there are no tables or rows": you store documents in collections, and documents can hold subcollections and nested objects. You design documents around the reads your screens make. Joins arrived in Firestore's Enterprise edition, through its pipeline operations.

Neither model is wrong. A chat app or a notes app is a pile of documents. A B2B SaaS, with accounts, members, roles, subscriptions and invoices that all refer to each other, is a set of tables.

Supabase RLS vs Firebase Security Rules

Both let your browser and phone app read the database directly, with access rules that live next to the data. The practical difference: RLS filters rows, while Firestore's Security Rules accept or reject the whole query.

In Supabase, a policy works like a WHERE clause added to every query. Here, members of a team see that team's projects, and a bare select * from projects returns only those rows:

create policy "members read projects" on public.projects
  for select to authenticated
  using (
    account_id in (
      select account_id from public.memberships
      where user_id = (select auth.uid())
    )
  );

Firestore works the other way round. Its guide to securing queries says "security rules are not filters—queries are all or nothing": if a query could return a document the user may not read, the whole request fails. Every query your app sends has to carry the same constraint the rule checks. A team rule looks like this:

rules_version = '2';
service cloud.firestore {
  match /databases/{database}/documents {
    match /teams/{teamId}/projects/{projectId} {
      allow read: if request.auth != null
        && exists(/databases/$(database)/documents/teams/$(teamId)/members/$(request.auth.uid));
    }
  }
}

That exists() call reads another document. According to Firebase's rules conditions docs, each such lookup is billed as a read, even when the request is denied, and a request gets at most 10 of them (20 for multi-document reads, transactions and batched writes).

Both have a way around the rules, and both must stay on your server. Supabase's secret key runs as service_role, which skips every policy. Firestore's server client libraries "bypass all Cloud Firestore Security Rules". Supabase anon key vs service role key covers which Supabase key goes where.

Is Firebase cheaper than Supabase?

At small scale both cost nothing; past that, it depends on how your app reads data. Firebase bills each document read, write and delete after a daily free quota, while Supabase bills a flat plan fee plus compute, with generous included usage.

Firebase, from its pricing page:

• Spark needs no payment method. Firestore includes 1 GiB stored, 50,000 reads, 20,000 writes and 20,000 deletes a day, and 10 GiB of egress a month. Authentication is no-cost up to 50,000 monthly active users.
• Blaze keeps the same free quotas, then bills at Google Cloud rates. Cloud Functions include 2 million invocations a month, then $0.40 per million.
• Cloud Storage needs Blaze. Since 3 February 2026, Spark projects can't reach any Cloud Storage bucket, default buckets included, according to Firebase's storage FAQ.
• Budget alerts don't stop spending. Firebase says they "do not cap your usage or charges". It recommends spend caps for Cloud Functions, App Hosting, AI Logic and Extensions, which pause new use of that service at its budget.
• Small reads add up. A query that returns nothing is still billed one read, and a listener is billed a read for every document added to or changed in its results.

Supabase's Free plan costs $0, with a 500 MB database, 5 GB of egress and 50,000 monthly active users, and it pauses projects after a quiet week. Pro starts at $25 a month and includes $10 of compute credits. Supabase pricing in 2026 has the full table and worked monthly bills.

The deciding factor is usually reads. A dashboard that lists 200 records costs Firestore 200 document reads every time someone opens it. On Supabase the same list is one query to a server you already pay for, and you're billed for the data it sends. Read-heavy B2B dashboards tend to favour Supabase's flat pricing; quiet apps with spiky traffic can sit inside Firebase's daily free quota.

How do Supabase Auth and Firebase Authentication compare?

Both handle email and password, phone numbers, OAuth providers and anonymous sign-in, and both are free up to 50,000 monthly active users. The differences are in the extras and in where users live.

• Supabase Auth includes 50,000 monthly active users on Free and 100,000 on Pro, then $0.00325 each. SAML SSO starts on Pro (50 users included, then $0.015 each), and phone MFA costs $75 a month. Users live in your Postgres database, so a policy can use auth.uid() directly.
• Firebase Authentication is no-cost up to 50,000 monthly active users, then Google Cloud pricing, and SAML or OIDC sign-in is free for 50 users. Phone sign-in is billed per SMS. Upgrading to Identity Platform adds multi-factor auth, blocking functions, audit logging, SAML and OpenID Connect, and multi-tenancy.

You can also mix them. Supabase accepts Firebase Auth as a third-party provider: the client passes the Firebase ID token, and you add a role: 'authenticated' claim so requests don't run as anon. If you're weighing a separate auth provider in general, Clerk vs Supabase Auth goes through that choice.

Supabase vs Firebase on lock-in and self-hosting

Supabase is easier to leave: your data sits in standard Postgres, and Supabase itself can be self-hosted. Firebase runs only as Google's service; its Local Emulator Suite runs on your machine, but Firebase says it is "not appropriate to use in production".

Supabase's self-hosting docs recommend Docker. Self-hosting is not the full platform: branching, managed backups and point-in-time recovery, and the Management API are among the missing features, and you run the servers, backups and monitoring yourself. Still, the exit exists, and pg_dump works on day one.

Leaving Firebase means changing data models. Supabase's own Firestore migration tool copies one collection into one Postgres table with text, numeric, boolean or jsonb columns, and anything nested needs your own script to split it into related tables.

What matters for a multi-tenant B2B SaaS?

Multi-tenant B2B data is relational: accounts have members, members have roles, and every row belongs to one account. That maps directly onto Postgres tables with an account_id and policies that check membership.

1. Checking membership. In Supabase, the policy looks up the memberships table, and an index on account_id keeps it fast. In Firestore, rules check membership with get() or exists(), each a billed read with a cap per request, or read it from custom claims.
2. Custom claims have limits. Firebase says the claims payload "must not exceed 1000 bytes", that only the Admin SDK should set it, and that new claims reach the client only when the ID token refreshes. A user in many teams can outgrow that space, and removing someone from a team waits for their next token.
3. Identity Platform tenants are not teams. Firebase's multi-tenancy creates "multiple unique silos of users and configurations within a single project". That suits customers who each bring their own sign-in setup. It is a different thing from one user belonging to several teams.
4. Billing and reporting. Seats, subscriptions and invoices refer to accounts. In SQL, counting seats per team or matching invoices to subscriptions is one query.
5. Testing isolation. With pgTAP you can sign in as one tenant inside a SQL test and try to read another tenant's rows. Firebase's Local Emulator Suite runs Firestore and Auth on your machine for tests and CI.

shipanysaas is built this way: one Supabase backend for a Next.js web app and an Expo phone app, RLS on all 13 tables, and pgTAP tests in which one account tries to read or change another's data. The details are in Row-level security, and teams, roles and invitations shows how to model the accounts themselves.

When is Firebase the better pick?

Pick Firebase when your app is mobile-first and must work offline, when your data is naturally a set of documents, or when you already build on Google Cloud.

• Offline-first mobile apps. Offline persistence is built into Firestore's SDKs, with no extra layer to add.
• Native SDKs beyond the usual. Unity and C++ alongside Swift, Kotlin and Flutter, which matters for games.
• Document-shaped data. Notes, chats, feeds and game state, where each screen reads a few documents and rarely joins.
• Low, spiky traffic. Daily free quotas cover quiet days at no cost.
• Your team knows it. Experience with Security Rules and the Firebase console is worth a lot.

When is Supabase the better pick?

Pick Supabase when your data is relational, when you want SQL and migrations you can review, or when you want a way out.

• Relational SaaS data. Teams, roles, subscriptions, invoices and audit logs.
• SQL. Joins, constraints, transactions, and migrations kept in git.
• Policies that filter. A list query that forgets its filter returns only the rows the user may see, instead of failing.
• Flat pricing for read-heavy apps. A $25 plan with compute included, not a bill per document read.
• Portability. Standard Postgres, and self-hosting if you ever need it.
• One client for web and phone. The same @supabase/supabase-js library runs in a Next.js app and an Expo app.

If you go with Supabase, Supabase RLS explained is the next thing to read.

FAQ

Is Supabase better than Firebase?

For relational, multi-tenant SaaS data, usually yes: SQL, policies that filter rows, and flat pricing. For offline-first mobile apps or document-shaped data, Firebase is often the better tool. Neither is better in general.

Is Firebase free?

The Spark plan is free and needs no payment method. It includes daily Firestore quotas (50,000 reads, 20,000 writes, 20,000 deletes) and Authentication up to 50,000 monthly active users. Cloud Functions and Cloud Storage need the pay-as-you-go Blaze plan.

Can I use Firebase Auth with Supabase?

Yes. Supabase supports Firebase Auth as a third-party provider. Your client passes the Firebase ID token, you add a role: 'authenticated' claim, and Supabase recommends restrictive policies that check the token's issuer and audience against your Firebase project ID.

Can I move from Firebase to Supabase later?

Yes, with work. Supabase documents migrations for Firestore data, Firebase Auth users and Firebase Storage. Users are exported to JSON and imported into auth.users, using your Firebase password hash parameters. Firestore collections arrive as flat tables, and nested data needs reshaping.

Does Supabase have realtime like Firebase?

Yes. Supabase Realtime has Broadcast for low-latency messages between clients, Presence for shared user state, and Postgres Changes for listening to database changes.