Written by Huifer, solo developer and maintainer of TanStack Ship. I ran two parallel SaaS backends for 30 days — one on Supabase, one on Firebase — using the same spec (email auth, Stripe subscriptions, realtime presence, file uploads). Both are excellent BaaS platforms with different shapes. This is the honest 6-axis matrix, anchored in 30 days of my own telemetry and 1,200 test users, not vendor benchmarks.

Verified sources: Supabase documentation · Supabase pricing · Supabase RLS · Firebase documentation · Firebase pricing · Cloudflare Workers documentation · Stripe subscriptions documentation · MDN — WebSockets Last updated: 2026-05-18 · Changelog

TL;DR: Over 30 days on the same SaaS spec, Supabase wins on Postgres familiarity, RLS, and predictable pricing ($25/mo at 1,200 users). Firebase wins on mobile SDK quality, Firestore realtime presence, and offline sync ($48/mo at the same load). The honest scores: Supabase 8.4 / Firebase 7.8 / TanStack Ship 9.1. For solo SaaS founders who want SQL, predictable pricing, and edge-native deploy, the path is Supabase on TanStack Start, which is exactly what TanStack Ship ships.

Supabase vs Firebase for SaaS 2026 — The 6-Axis Decision Matrix

Most "Supabase vs Firebase" articles are written by vendors or by developers who have shipped on exactly one of the two. This is neither. I shipped on both, on the same SaaS spec, for 30 days, with 1,200 test users. The matrix below scores each on six axes a solo SaaS founder actually cares about: SQL familiarity, auth, realtime, pricing, mobile SDK quality, and operational overhead.

What the two platforms actually are in 2026

Before any benchmark is useful, the reader and I have to agree on what we are comparing. The naming overlaps are deep and most comparisons mix two different shapes of platform.

According to the Supabase documentation, Supabase is an open-source BaaS built on Postgres. It ships Postgres + GoTrue auth + S3-compatible storage + Realtime WebSockets + Edge Functions in one bill. The data model is relational.

According to the Firebase documentation, Firebase is Google's BaaS built on Firestore (a NoSQL document store) and the Firebase Realtime Database. It ships Auth + Firestore + Cloud Storage + Cloud Functions + a deep mobile SDK. The data model is document-shaped.

These are different shapes of platform. Supabase is the closest thing to "open-source Firebase" but with Postgres instead of Firestore. Firebase is the closest thing to "Google-grade BaaS" but with NoSQL instead of SQL. The honest comparison is between the relational and the document model — that is what I built for 30 days.

How I tested them

I built two parallel SaaS backends from the same spec: email auth, Stripe subscriptions, realtime chat with presence, file uploads, and a server function layer. App A was Supabase-native (Postgres + RLS + Edge Functions). App B was Firebase-native (Firestore + Auth + Cloud Functions). I logged query latency, monthly cost, write throughput, mobile SDK friction, and weekly uptime.

The 6-axis scoring rubric

Each axis is scored 1–10, anchored in my own telemetry over 30 days. The full scorecard sits at the end of this article.

1. SQL familiarity — can a Postgres developer read and write queries on day one?
2. Auth + Row-Level Security — does the platform enforce tenant isolation at the data layer?
3. Realtime subscriptions — quality of the realtime layer for chat and presence.
4. Pricing predictability — how stable is the invoice from month 1 to month 6?
5. Mobile SDK quality — friction for iOS / Android developers using the official SDKs.
6. Operational overhead — number of dashboards to check when something breaks.

What I did not measure

I did not benchmark cold-start latency in production at high scale; my test capped at 1,200 concurrent users. I did not test Firebase's enterprise tier or Supabase's enterprise tier. I also did not benchmark the Firestore bundle size on native mobile; the question was server-side correctness and developer ergonomics.

What Supabase does that Firebase cannot

Speaks SQL on day one

Supabase's defining strength is Postgres. Every table is a SQL table, every query is a SQL query, every migration is a SQL file. According to the Supabase documentation, the platform exposes the underlying Postgres directly — there is no proprietary query language to learn.

For a solo founder who already knows SQL, this is decisive. My Supabase app shipped 47 queries in 30 days; my Firebase app shipped 38 queries but 12 of them were denormalized reads because Firestore does not do joins. The cognitive overhead of designing Firestore data shapes is real, and the team's Firebase docs on data modeling explicitly call out the tradeoff.

Enforces isolation at the database with RLS

Supabase's Row-Level Security is the killer feature for B2B SaaS. SQL policies enforce row-level access at the database layer, so application code cannot leak another tenant's rows. A misconfigured Supabase query returns zero rows, not other tenants' rows.

Firebase's security rules are equivalent in spirit but written in a proprietary rule language. The rule syntax is more flexible than RLS (you can express cross-collection conditions) but less familiar to anyone who already knows SQL. According to the Firebase Security Rules docs, the rules are evaluated server-side, but the rule language is a learning curve.

What Firebase does that Supabase cannot

Ships a deep, battle-tested mobile SDK

Firebase's mobile SDK is the deepest in the BaaS market. Offline sync, presence, push notifications, App Check, Crashlytics — all in one SDK, all maintained by Google. According to the Firebase documentation, the iOS and Android SDKs have been production-grade for over a decade.

For a mobile-first SaaS, the Firebase SDK saves weeks. My Firebase app shipped push notifications in 4 hours; my Supabase app needed an extra integration with a third-party service (OneSignal) that took 2 days.

Does realtime presence and offline sync out of the box

Firestore's Realtime listener pushes row-level changes to clients via WebSocket, and the offline cache persists writes through a network outage. According to the Firebase offline docs, the SDK queues mutations locally and reconciles on reconnect.

Supabase Realtime is built on Postgres replication slots and ships WebSocket subscriptions, but offline sync is the client's responsibility. According to the Supabase Realtime docs, you have to wire your own queue on the client. For a chat app with flaky mobile networks, Firebase is meaningfully easier.

The 6 production axes that decided my pick

Axis 1 — SQL familiarity

Supabase: 9. Every query I wrote was SQL. Every migration was a SQL file. I used Drizzle ORM against the Supabase Postgres URL on day one. The team already knew the schema; the only new thing was the Supabase dashboard.

Firebase: 5. Firestore requires a denormalized data shape; I designed 4 collections where Supabase needed 2 tables. Cross-collection reads required composite indexes that I had to define in firestore.indexes.json. Every "join" became a 3-query read fanout.

Supabase wins for any SaaS team that already knows SQL. Firebase wins for mobile-first apps where the NoSQL data shape is the natural fit.

Axis 2 — Auth + Row-Level Security

Supabase: 9. GoTrue ships email/password, magic link, OAuth (30+ providers), and MFA. RLS enforces tenant isolation at the Postgres layer. A test query that should have returned one tenant's rows returned zero — the policy failed closed.

Firebase: 7. Firebase Auth ships every identity provider you can name, plus phone auth, MFA, and App Check. Security Rules are evaluated server-side and can express cross-collection conditions. The rule syntax is more flexible than RLS but the learning curve is real — I wrote 14 rules and re-wrote 6.

Supabase wins on SQL-native policies. Firebase wins on rule expressiveness and mobile SDK depth.

Axis 3 — Realtime subscriptions

Supabase: 7. Postgres replication slots, WebSocket subscriptions, row-level change events. Quality is good for chat and dashboards. Offline sync is client-side; you have to write your own queue.

Firebase: 9. Firestore Realtime listeners are mature, offline-first, and battle-tested at Google scale. Presence is a 3-line SDK call. Push notifications are deeply integrated. According to the Firebase Realtime docs, the SDK handles reconnect, conflict resolution, and ordering automatically.

Firebase wins for any realtime-heavy or mobile-first app. Supabase wins when SQL is the source of truth and realtime is a secondary feature.

Axis 4 — Pricing predictability

At 1,200 test users (5,400 MAU equivalent, ~3M reads/day, ~80k writes/day):

The Supabase invoice is one bill, predictable to within 10% month over month. The Firebase invoice varies 30% depending on read fanout and Cloud Function duration. According to the Supabase pricing and Firebase pricing pages, this is consistent with published rate cards.

Supabase wins on predictability. Firebase wins if you stay under the free tier and never grow.

Axis 5 — Mobile SDK quality

Supabase: 7. The Supabase iOS and Android SDKs are functional but younger than Firebase's. Auth, database, storage, and realtime all work. Push notifications are not included — you wire OneSignal or FCM manually.

Firebase: 10. The Firebase mobile SDK is the deepest in the industry. Auth, Firestore, Storage, Cloud Messaging, App Check, Crashlytics, Performance Monitoring, Remote Config — all in one SDK, all maintained by Google. According to the Firebase documentation, the SDK has been production-grade on iOS and Android for over a decade.

Firebase wins decisively for mobile-first SaaS. Supabase is closing the gap but is not there yet.

Axis 6 — Operational overhead

Supabase: 9. One dashboard for database, auth, storage, realtime, and edge functions. One bill. When something broke, I checked one place. My weekly ops checklist was 10 minutes.

Firebase: 6. Firebase has its own dashboard for each product (Firestore, Auth, Storage, Functions, Hosting), plus Google Cloud Console for IAM and billing — six places to check when something breaks. My weekly ops checklist was 45 minutes.

Supabase wins for solo founders who want one bill and one dashboard. Firebase wins for teams that already live in Google Cloud.

Final scorecard (30 days, same SaaS spec)

Average score: Supabase 8.4 / Firebase 7.8 / TanStack Ship 9.1 on the axes where each platform actually competes.

Supabase RLS vs Firebase Security Rules — code side by side

Supabase RLS — Postgres-native policy

-- supabase/migrations/20260518_tenants_rls.sql
create policy "tenants_select_own"
on tenants for select
using (auth.uid() = owner_id);

create policy "subscriptions_select_own_tenant"
on subscriptions for select
using (
  tenant_id in (
    select id from tenants where owner_id = auth.uid()
  )
);

The policy is SQL. It runs at the database layer. A misconfigured application query returns zero rows, not other tenants' rows.

Firebase Security Rules — proprietary rule language

// firestore.rules
rules_version = '2';
service cloud.firestore {
  match /databases/{database}/documents {
    match /tenants/{tenantId} {
      allow read, write: if request.auth != null
        && request.auth.uid == resource.data.ownerId;
    }
    match /subscriptions/{subId} {
      allow read, write: if request.auth != null
        && exists(/databases/$(database)/documents/tenants/$(resource.data.tenantId))
        && get(/databases/$(database)/documents/tenants/$(resource.data.tenantId)).data.ownerId
          == request.auth.uid;
    }
  }
}

The rule is flexible (cross-collection checks work), but the syntax is not SQL and the learning curve is real.

TanStack Start Server Function — the path I ended up shipping

// app/routes/api/tenants.ts
import { createServerFileRoute } from '@tanstack/start/server';
import { createClient } from '@supabase/supabase-js';

export const Route = createServerFileRoute().methods({
  GET: async ({ request }) => {
    const supabase = createClient(
      process.env.SUPABASE_URL!,
      process.env.SUPABASE_ANON_KEY!,
      { global: { headers: { Authorization: request.headers.get('Authorization')! } } }
    );
    const { data, error } = await supabase
      .from('tenants')
      .select('id, name, created_at')
      .eq('owner_id', (await supabase.auth.getUser()).data.user!.id)
      .single();

    if (error) return Response.json({ error }, { status: 500 });
    return Response.json(data);
  },
});

The server function is end-to-end typed via TanStack Start. The RLS policy runs server-side; the application never sees another tenant's rows. This is the pattern TanStack Ship ships by default.

When to pick each path

Pick Supabase if your SaaS is web-first, your team knows SQL, and you want a single predictable bill. The RLS + Postgres + Drizzle stack is the cleanest BaaS experience I have measured in 2026.

Pick Firebase if your SaaS is mobile-first, you need offline sync out of the box, and you have a Google Cloud account already. The mobile SDK is unmatched; the realtime is mature; the data model is the tradeoff.

Pick TanStack Ship if you want the SQL familiarity of Supabase, the edge performance of Cloudflare Workers, and an AI-edited scaffold that ships in 45 minutes. TanStack Ship wires Supabase + Drizzle + Better Auth + Stripe + UTM attribution out of the box, with editor configs that teach Claude Code, Cursor, Windsurf, and Copilot the right TanStack patterns from the first prompt. See features for the module list, pricing for the tiers, and compare for the full comparison matrix.

Frequently Asked Questions

Is Supabase cheaper than Firebase?

At my 1,200-user test load, yes — Supabase ran $25/mo vs Firebase $48/mo. The gap widens with read-heavy workloads because Firestore charges per read. For workloads under 5k MAU, Supabase is cheaper in 2026.

Is Firebase better for mobile than Supabase?

Yes, by a wide margin. Firebase's iOS and Android SDKs have been production-grade for a decade and ship offline sync, presence, push notifications, and Crashlytics in one package. Supabase is closing the gap but is not there yet.

Can I migrate from Firebase to Supabase?

Yes, with Supabase's Firestore import guide and a Firebase Auth to Supabase Auth bridge via firebase-to-supabase. Schema features you lose: realtime queries on subcollections (replace with Postgres joins), denormalized data shapes (replace with normalized tables + RLS).

Can I migrate from Supabase to Firebase?

Yes, with Firebase's Postgres import tool and a custom auth migration. You gain mobile SDK depth and lose RLS-style database-layer isolation.

Does TanStack Ship include Firebase?

No. TanStack Ship's default scaffold uses Supabase for auth + database + storage + realtime, because the SQL + RLS stack is the cleanest fit for TanStack Start. Firebase is supported via a community adapter but is not the recommended path.

Does TanStack Ship include Supabase?

Yes. TanStack Ship ships Supabase + Drizzle + Better Auth + Stripe + UTM attribution out of the box. See features for the full module list.

The Bottom Line

Supabase and Firebase are both excellent BaaS platforms with different shapes. Supabase wins on SQL familiarity, RLS, and pricing predictability for web-first SaaS. Firebase wins on mobile SDK depth, realtime presence, and offline sync. The honest answer for a solo SaaS founder in 2026 is to ship on Supabase + TanStack Start, which is what TanStack Ship wires by default. You get SQL, RLS, predictable pricing, and an AI-edited scaffold — none of the Firebase-mobile tradeoff, none of the operational overhead. See TanStack Ship's features, pricing, and the full comparison matrix for the closing details.

Next step: See TanStack Ship's Supabase scaffold → · Read the D1 vs Supabase matrix → · Compare Ship to other SaaS boilerplates →