Supabase vs Firebase - A Comprehensive Backend-as-a-Service Comparison

Backend-as-a-Service (BaaS) is revolutionizing how applications are built, allowing developers to focus on business logic instead of managing infrastructure. Two platforms dominate this space: Firebase - Google's mature product with a massive ecosystem, and Supabase - an open-source alternative built on PostgreSQL that is rapidly gaining popularity. In this article, we will thoroughly compare both solutions so you can make an informed decision when choosing the backend for your project.

Database - PostgreSQL vs Firestore/Realtime Database#

Supabase - The Full Power of PostgreSQL#

Supabase uses PostgreSQL - one of the most mature and advanced relational databases in the world. This means full support for SQL, complex queries, table relationships, indexes, triggers, views, and stored procedures. Each project receives a dedicated PostgreSQL instance with full access.

import { createClient } from '@supabase/supabase-js';

const supabase = createClient(
  process.env.SUPABASE_URL!,
  process.env.SUPABASE_ANON_KEY!
);

// Query with relationships - automatic JOIN
const { data: posts, error } = await supabase
  .from('posts')
  .select(`
    id,
    title,
    content,
    created_at,
    author:users (
      id,
      name,
      avatar_url
    ),
    comments (
      id,
      body,
      user:users (name)
    )
  `)
  .eq('published', true)
  .order('created_at', { ascending: false })
  .range(0, 9);

Thanks to PostgreSQL, you also get support for extensions such as PostGIS (geographic data), pg_cron (scheduled jobs), pgvector (vector search for AI), and pg_stat_statements (query performance analysis).

Firebase - Firestore and Realtime Database#

Firebase offers two NoSQL databases. Cloud Firestore is the newer, recommended option - a document database with automatic scaling and a rich query system. Realtime Database is the older, simpler JSON database ideal for real-time synchronization.

import { initializeApp } from 'firebase/app';
import {
  getFirestore, collection, query, where, orderBy, limit, getDocs
} from 'firebase/firestore';

const app = initializeApp(firebaseConfig);
const db = getFirestore(app);

// Firestore query - limited JOIN capabilities
const postsQuery = query(
  collection(db, 'posts'),
  where('published', '==', true),
  orderBy('createdAt', 'desc'),
  limit(10)
);

const snapshot = await getDocs(postsQuery);
const posts = snapshot.docs.map(doc => ({ id: doc.id, ...doc.data() }));

// Author data must be fetched separately
for (const post of posts) {
  const authorDoc = await getDoc(doc(db, 'users', post.authorId));
  post.author = authorDoc.data();
}

The key difference: Firestore requires data denormalization - copying information between collections to avoid multiple queries. PostgreSQL in Supabase allows classical normalized schemas with relationships.

Authentication (Auth)#

Supabase Auth#

Supabase offers a complete authentication system based on GoTrue with support for over 20 OAuth providers, magic links, OTP via SMS and email, and SAML authentication for enterprise clients.

// Email/password registration
const { data, error } = await supabase.auth.signUp({
  email: 'user@example.com',
  password: 'securePassword123',
  options: { data: { full_name: 'John Smith', role: 'user' } }
});

// OAuth login
const { data, error } = await supabase.auth.signInWithOAuth({
  provider: 'google',
  options: { redirectTo: 'https://myapp.com/auth/callback', scopes: 'email profile' }
});

// Listen for auth state changes
supabase.auth.onAuthStateChange((event, session) => {
  if (event === 'SIGNED_IN') {
    console.log('Logged in:', session?.user.email);
  }
});

A major advantage of Supabase Auth is its direct integration with Row Level Security - database security policies automatically recognize the logged-in user.

Firebase Authentication#

Firebase Auth is one of the most mature authentication systems in the BaaS ecosystem, with support for many providers and excellent integration with other Firebase services.

import {
  getAuth, createUserWithEmailAndPassword, signInWithPopup,
  GoogleAuthProvider, onAuthStateChanged
} from 'firebase/auth';

const auth = getAuth();

const userCredential = await createUserWithEmailAndPassword(
  auth, 'user@example.com', 'securePassword123'
);

const provider = new GoogleAuthProvider();
provider.addScope('email');
provider.addScope('profile');
const result = await signInWithPopup(auth, provider);

onAuthStateChanged(auth, (user) => {
  if (user) { console.log('Logged in:', user.email); }
});

Both systems offer comparable functionality, but Supabase stands out with its native database integration through RLS, while Firebase requires configuring security rules in a separate file.

Storage - File Storage#

Supabase Storage#

Supabase Storage is built on an S3-compatible storage system with RLS-based security policies. It supports image transformations (resize, crop) without additional services.

const { data, error } = await supabase.storage
  .from('avatars')
  .upload(`users/${userId}/avatar.webp`, file, {
    contentType: 'image/webp', upsert: true
  });

const { data: urlData } = supabase.storage
  .from('avatars')
  .getPublicUrl(`users/${userId}/avatar.webp`, {
    transform: { width: 200, height: 200, resize: 'cover', quality: 80 }
  });

Firebase Cloud Storage#

Firebase Cloud Storage is based on Google Cloud Storage and offers solid file storage capabilities with security rules.

import { getStorage, ref, uploadBytes, getDownloadURL } from 'firebase/storage';
const storage = getStorage();
const storageRef = ref(storage, `avatars/${userId}/avatar.webp`);
await uploadBytes(storageRef, file, { contentType: 'image/webp' });
const downloadURL = await getDownloadURL(storageRef);

Firebase requires a separate service for image transformations, while Supabase offers this natively.

Edge Functions vs Cloud Functions#

Supabase Edge Functions#

Supabase Edge Functions are serverless functions based on Deno, running at the network edge with minimal latency. They support TypeScript natively.

import { serve } from 'https://deno.land/std@0.177.0/http/server.ts';
import { createClient } from 'https://esm.sh/@supabase/supabase-js@2';

serve(async (req: Request) => {
  const supabase = createClient(
    Deno.env.get('SUPABASE_URL')!, Deno.env.get('SUPABASE_SERVICE_ROLE_KEY')!
  );
  const { userId } = await req.json();
  const { data: user } = await supabase
    .from('users').select('email, full_name').eq('id', userId).single();

  await fetch('https://api.resend.com/emails', {
    method: 'POST',
    headers: {
      'Authorization': `Bearer ${Deno.env.get('RESEND_API_KEY')}`,
      'Content-Type': 'application/json'
    },
    body: JSON.stringify({
      from: 'welcome@myapp.com', to: user?.email,
      subject: `Welcome, ${user?.full_name}!`,
      html: '<h1>Welcome to our application!</h1>'
    })
  });

  return new Response(JSON.stringify({ success: true }), {
    headers: { 'Content-Type': 'application/json' }
  });
});

Firebase Cloud Functions#

Firebase Cloud Functions run on Google Cloud infrastructure and support Node.js. They offer deep integration with Firestore, Auth, and other Firebase service triggers.

import { onDocumentCreated } from 'firebase-functions/v2/firestore';
import { getFirestore } from 'firebase-admin/firestore';
import * as admin from 'firebase-admin';

admin.initializeApp();

export const onUserCreated = onDocumentCreated('users/{userId}', async (event) => {
  const snapshot = event.data;
  if (!snapshot) return;
  const userData = snapshot.data();
  const db = getFirestore();
  await db.collection('mail').add({
    to: userData.email,
    message: {
      subject: `Welcome, ${userData.fullName}!`,
      html: '<h1>Welcome to our application!</h1>'
    }
  });
});

Firebase Cloud Functions offer richer triggers (Firestore, Auth, Pub/Sub, Scheduler), while Supabase Edge Functions have lower latency thanks to running at the network edge.

Real-time Subscriptions#

Supabase Realtime#

Supabase offers real-time subscriptions based on WebSocket with support for three channel types: database changes (Postgres Changes), presence (Presence), and broadcasting (Broadcast).

const channel = supabase
  .channel('posts-changes')
  .on('postgres_changes',
    { event: '*', schema: 'public', table: 'posts', filter: 'published=eq.true' },
    (payload) => { console.log('Change in posts:', payload.eventType, payload.new); }
  )
  .subscribe();

const presenceChannel = supabase.channel('online-users');
presenceChannel
  .on('presence', { event: 'sync' }, () => {
    const state = presenceChannel.presenceState();
    console.log('Online:', Object.keys(state).length);
  })
  .subscribe(async (status) => {
    if (status === 'SUBSCRIBED') {
      await presenceChannel.track({ user_id: currentUser.id, online_at: new Date().toISOString() });
    }
  });

Firebase Realtime Listeners#

Firebase offers native change listeners in Firestore and Realtime Database with automatic offline synchronization.

import { collection, query, where, onSnapshot, orderBy } from 'firebase/firestore';

const postsQuery = query(
  collection(db, 'posts'), where('published', '==', true), orderBy('createdAt', 'desc')
);

const unsubscribe = onSnapshot(postsQuery, (snapshot) => {
  snapshot.docChanges().forEach((change) => {
    if (change.type === 'added') console.log('New post:', change.doc.data());
    if (change.type === 'modified') console.log('Modified post:', change.doc.data());
    if (change.type === 'removed') console.log('Removed post:', change.doc.data());
  });
});

Firebase has the advantage of built-in offline synchronization - data is automatically cached and synchronized when the connection is restored. Supabase requires additional implementation for this functionality.

Row Level Security (RLS)#

Supabase RLS - Database-Level Security#

One of Supabase's strongest features is native support for PostgreSQL Row Level Security. Security policies are defined directly in the database and enforced on every query - regardless of whether it comes from a client, API, or Edge Function.

-- Users can read only published posts or their own drafts
CREATE POLICY "read_posts" ON posts FOR SELECT USING (
  published = true OR auth.uid() = author_id
);

-- Users can edit only their own posts
CREATE POLICY "update_own_posts" ON posts FOR UPDATE USING (
  auth.uid() = author_id
);

-- Users can delete posts only if they have the admin role
CREATE POLICY "admin_delete" ON posts FOR DELETE USING (
  EXISTS (SELECT 1 FROM user_roles WHERE user_id = auth.uid() AND role = 'admin')
);

Firebase Security Rules#

Firebase uses a separate security rules system defined in a JSON file or special DSL. Supabase RLS has the advantage - policies are part of the database, meaning they work regardless of how the data is accessed. Firebase Security Rules only apply to requests coming through the Firebase SDK, and direct access via the Admin SDK bypasses them.

Open Source vs Proprietary#

Supabase - Fully Open Source#

Supabase is fully open-source (Apache 2.0 license). The entire platform code is available on GitHub, which means transparency, self-hosting capability, no vendor lock-in, community contributions, and easier security audits.

Firebase - Proprietary with Open Source Elements#

Firebase is a closed-source product of Google Cloud. Some SDKs and client tools are open source, but the platform and infrastructure itself remain Google's property. Firebase offers local emulators for development, but you cannot run your own Firebase instance.

Self-Hosting#

Supabase self-hosting is fully supported and documented. You can run your own instance on any server with Docker, Kubernetes, or cloud providers. Firebase does not offer self-hosting.

Pricing#

Supabase - Predictable Costs#

| Plan | Price | Includes | |------|-------|----------| | Free | $0/mo | 500 MB database, 1 GB storage, 2 GB transfer, 50k MAU | | Pro | $25/mo | 8 GB database, 100 GB storage, 250 GB transfer, 100k MAU | | Team | $599/mo | Higher limits, SOC2, priority support | | Enterprise | Custom | Dedicated infrastructure, SLA |

Firebase - Pay-as-you-go#

| Service | Free tier | Paid rate | |---------|-----------|-----------| | Firestore - reads | 50k/day | $0.06/100k | | Firestore - writes | 20k/day | $0.18/100k | | Auth | 10k/mo SMS | $0.06/SMS verification | | Storage | 5 GB | $0.026/GB | | Cloud Functions | 2M invocations | $0.40/million |

Firebase can be cheaper for small projects, but costs grow quickly with high traffic and can be difficult to predict.

Comparison Table#

| Feature | Supabase | Firebase | |---------|----------|----------| | Database | PostgreSQL (relational) | Firestore/RTDB (NoSQL) | | Query language | SQL | SDK / limited queries | | Auth | GoTrue (20+ providers) | Firebase Auth (20+ providers) | | Storage | S3-compatible + transformations | Google Cloud Storage | | Functions | Edge Functions (Deno) | Cloud Functions (Node.js) | | Real-time | WebSocket + Presence + Broadcast | Native listeners + offline sync | | Security | Row Level Security (SQL) | Security Rules (DSL) | | API | Auto-generated REST + GraphQL | SDK-first | | Open Source | Yes (Apache 2.0) | Partially (SDKs) | | Self-hosting | Yes (Docker/K8s) | No | | Vendor lock-in | Low | High | | Offline sync | Requires implementation | Built-in | | Pricing | Predictable (plan) | Pay-as-you-go | | Maturity | Young (2020) | Mature (2012) | | Learning curve | Requires SQL knowledge | Easier start |

When to Choose Supabase?#

• You need a relational database with complex queries
• You value open source and no vendor lock-in
• You require self-hosting (regulations, data privacy)
• You want to use PostgreSQL and its extensions
• You need an automatic REST/GraphQL API
• Database-level Row Level Security is a priority

When to Choose Firebase?#

• You are building a mobile application with native offline support
• You need rapid prototyping without SQL knowledge
• You use the Google Cloud ecosystem
• You need mature SDKs for multiple platforms (including Unity)
• A denormalized data model fits your use case
• You want to use the rich Firebase Extensions ecosystem

Summary#

Both Supabase and Firebase are powerful BaaS platforms, but they serve different philosophies. Supabase is the choice for developers who value openness, standard technologies (PostgreSQL, SQL), and full control over data. Firebase works best for rapid prototyping of mobile applications with offline synchronization requirements and deep integration with the Google ecosystem.

The industry trend clearly points to growing popularity of Supabase, especially among web developers and startups looking for predictable costs and no vendor lock-in. However, Firebase remains irreplaceable in scenarios requiring native offline support and broad mobile platform coverage.

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Need a Professional Backend for Your Application?#

At MDS Software Solutions Group, we specialize in implementing Backend-as-a-Service solutions on both Supabase and Firebase. Our team will help you choose the optimal platform, design the database architecture, configure authentication and security, and implement a complete backend solution tailored to your business needs.

Contact us to discuss your project - from architectural consulting to full implementation.