Supabase vs Firebase : Le Comparatif Complet des BaaS en 2025

En 2025, Supabase s'affirme comme l'alternative open-source à Firebase. PostgreSQL vs Firestore, Row Level Security vs Rules, pricing transparent vs complexe : découvrez quel Backend-as-a-Service correspond à vos besoins.

🚀 Vue d'Ensemble

Firebase : L'écosystème Google

Firebase domine le marché BaaS depuis 2014 avec son intégration Google Cloud et sa simplicité d'utilisation.

Points forts :

• Firestore (NoSQL temps réel)
• Authentication complète
• Cloud Functions
• Hosting gratuit
• Intégration Google Analytics
• SDKs matures (15+ plateformes)

Supabase : L'alternative open-source

Supabase, lancé en 2020, propose une alternative basée sur PostgreSQL avec philosophie open-source.

Points forts :

• PostgreSQL (SQL relationnelle)
• Row Level Security (RLS)
• Real-time subscriptions
• Auto-generated REST APIs
• Edge Functions (Deno)
• Self-hosting possible

💡 Base de Données : PostgreSQL vs Firestore

Supabase (PostgreSQL)

// Supabase: SQL relationnel avec types forts
import { createClient } from '@supabase/supabase-js';

const supabase = createClient(
  'https://your-project.supabase.co',
  'your-anon-key'
);

// Typage automatique avec CLI
type User = Database['public']['Tables']['users']['Row'];

// Queries SQL-like avec TypeScript
const { data: users, error } = await supabase
  .from('users')
  .select(`
    id,
    name,
    email,
    posts (
      id,
      title,
      created_at
    )
  `)
  .eq('age', 30)
  .order('created_at', { ascending: false })
  .limit(10);

// Transactions complexes possibles
const { data, error } = await supabase.rpc('transfer_funds', {
  from_account: 123,
  to_account: 456,
  amount: 100
});

// Fonctions PostgreSQL custom
// SQL:
// CREATE FUNCTION transfer_funds(from_account INT, to_account INT, amount DECIMAL)
// RETURNS JSON AS $$
// BEGIN
//   UPDATE accounts SET balance = balance - amount WHERE id = from_account;
//   UPDATE accounts SET balance = balance + amount WHERE id = to_account;
//   RETURN json_build_object('success', true);
// END;
// $$ LANGUAGE plpgsql;

Firebase (Firestore)

// Firebase: NoSQL document-oriented
import { initializeApp } from 'firebase/app';
import { getFirestore, collection, query, where, getDocs, orderBy, limit } from 'firebase/firestore';

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

// Queries NoSQL (moins flexibles que SQL)
const usersRef = collection(db, 'users');
const q = query(
  usersRef,
  where('age', '==', 30),
  orderBy('createdAt', 'desc'),
  limit(10)
);

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

// Sous-collections (pas de JOIN natif)
const userDoc = doc(db, 'users', userId);
const postsRef = collection(userDoc, 'posts');
const postsSnapshot = await getDocs(postsRef);

// Transactions
await runTransaction(db, async (transaction) => {
  const fromDoc = await transaction.get(doc(db, 'accounts', '123'));
  const toDoc = await transaction.get(doc(db, 'accounts', '456'));

  const newFromBalance = fromDoc.data().balance - 100;
  const newToBalance = toDoc.data().balance + 100;

  transaction.update(doc(db, 'accounts', '123'), { balance: newFromBalance });
  transaction.update(doc(db, 'accounts', '456'), { balance: newToBalance });
});

Comparaison données

🔐 Authentication : Comparable mais Différent

Supabase Auth

// Email/Password signup
const { data, error } = await supabase.auth.signUp({
  email: 'user@example.com',
  password: 'secure_password',
  options: {
    data: {
      full_name: 'John Doe',
      age: 30
    }
  }
});

// OAuth providers (12+ supportés)
const { data, error } = await supabase.auth.signInWithOAuth({
  provider: 'google',
  options: {
    redirectTo: 'https://yourapp.com/callback'
  }
});

// Magic link (passwordless)
const { data, error } = await supabase.auth.signInWithOtp({
  email: 'user@example.com',
  options: {
    emailRedirectTo: 'https://yourapp.com/verify'
  }
});

// Session management
const { data: { session } } = await supabase.auth.getSession();
const user = session?.user;

// Row Level Security (RLS) intégré
// SQL:
// CREATE POLICY "Users can only see their own data"
// ON public.users
// FOR SELECT
// USING (auth.uid() = id);

Firebase Auth

// Email/Password signup
import { getAuth, createUserWithEmailAndPassword, updateProfile } from 'firebase/auth';

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

await updateProfile(userCredential.user, {
  displayName: 'John Doe'
});

// OAuth providers (30+ supportés)
import { signInWithPopup, GoogleAuthProvider } from 'firebase/auth';

const provider = new GoogleAuthProvider();
const result = await signInWithPopup(auth, provider);
const user = result.user;

// Email link (passwordless)
import { sendSignInLinkToEmail } from 'firebase/auth';

await sendSignInLinkToEmail(auth, 'user@example.com', {
  url: 'https://yourapp.com/verify',
  handleCodeInApp: true
});

// Session management
import { onAuthStateChanged } from 'firebase/auth';

onAuthStateChanged(auth, (user) => {
  if (user) {
    console.log('User logged in:', user.uid);
  }
});

Comparaison Auth

⚡ Real-time : Approches Différentes

Supabase Real-time

// Supabase: PostgreSQL real-time via WebSocket
const channel = supabase
  .channel('public:posts')
  .on(
    'postgres_changes',
    {
      event: 'INSERT',
      schema: 'public',
      table: 'posts'
    },
    (payload) => {
      console.log('New post:', payload.new);
    }
  )
  .on(
    'postgres_changes',
    {
      event: 'UPDATE',
      schema: 'public',
      table: 'posts',
      filter: 'author_id=eq.123'
    },
    (payload) => {
      console.log('Post updated:', payload.new);
    }
  )
  .subscribe();

// Presence (qui est en ligne)
const presence = supabase.channel('room:1');

presence
  .on('presence', { event: 'sync' }, () => {
    const state = presence.presenceState();
    console.log('Online users:', Object.keys(state));
  })
  .on('presence', { event: 'join' }, ({ key, newPresences }) => {
    console.log('User joined:', key);
  })
  .subscribe(async (status) => {
    if (status === 'SUBSCRIBED') {
      await presence.track({ user: 'Alice', online_at: new Date().toISOString() });
    }
  });

Firebase Real-time

// Firebase: Firestore real-time listeners
import { onSnapshot } from 'firebase/firestore';

// Écouter les changements d'un document
const unsubscribe = onSnapshot(
  doc(db, 'posts', 'post123'),
  (doc) => {
    console.log('Document updated:', doc.data());
  }
);

// Écouter une collection avec query
const q = query(collection(db, 'posts'), where('authorId', '==', '123'));

const unsubscribe = onSnapshot(q, (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());
    }
  });
});

// Realtime Database (legacy, plus rapide pour certains cas)
import { getDatabase, ref, onValue } from 'firebase/database';

const rtdb = getDatabase();
const presenceRef = ref(rtdb, 'presence/user123');

onValue(presenceRef, (snapshot) => {
  const data = snapshot.val();
  console.log('User status:', data);
});

🔧 Edge Functions vs Cloud Functions

Supabase Edge Functions (Deno)

// Supabase: Edge Functions avec Deno
// supabase/functions/hello/index.ts

import { serve } from 'https://deno.land/std@0.168.0/http/server.ts';
import { createClient } from 'https://esm.sh/@supabase/supabase-js@2';

serve(async (req) => {
  // Accès à Supabase depuis la fonction
  const supabase = createClient(
    Deno.env.get('SUPABASE_URL') ?? '',
    Deno.env.get('SUPABASE_ANON_KEY') ?? ''
  );

  // Parse request
  const { name } = await req.json();

  // Query database
  const { data, error } = await supabase
    .from('users')
    .select('*')
    .eq('name', name)
    .single();

  // Return response
  return new Response(JSON.stringify({ user: data }), {
    headers: { 'Content-Type': 'application/json' }
  });
});

// Deploy: supabase functions deploy hello
// Performance: cold start ~50-100ms

Firebase Cloud Functions

// Firebase: Cloud Functions avec Node.js
import { onRequest } from 'firebase-functions/v2/https';
import { initializeApp } from 'firebase-admin/app';
import { getFirestore } from 'firebase-admin/firestore';

initializeApp();

export const hello = onRequest(async (request, response) => {
  const db = getFirestore();

  // Parse request
  const { name } = request.body;

  // Query Firestore
  const snapshot = await db
    .collection('users')
    .where('name', '==', name)
    .limit(1)
    .get();

  const user = snapshot.docs[0]?.data();

  // Return response
  response.json({ user });
});

// Deploy: firebase deploy --only functions
// Performance: cold start ~1-3 secondes (Node.js)

Comparaison Functions

💰 Pricing : Transparence vs Complexité

Supabase Pricing (2025)

**Free Tier**:
- 500 MB database
- 1 GB file storage
- 2 GB bandwidth
- 500K Edge Function invocations
- Paused après 7 jours inactivité

**Pro ($25/mois)**:
- 8 GB database
- 100 GB storage
- 250 GB bandwidth
- 2M Edge Function invocations
- Daily backups

**Team ($599/mois)**:
- Ressources plus larges
- Priority support
- SOC2 compliance

**Enterprise**: Custom pricing

Firebase Pricing (2025)

**Spark (Free)**:
- 1 GB stored
- 10 GB/month bandwidth
- 50K document reads/day
- 20K document writes/day
- 125K Cloud Functions invocations/mois

**Blaze (Pay as you go)**:
- Firestore: $0.06 / 100K reads, $0.18 / 100K writes
- Storage: $0.026/GB
- Bandwidth: $0.12/GB
- Functions: $0.40 / million invocations + compute time
- Peut devenir cher rapidement !

**Exemple coût moyen**:
100K users actifs/mois: $200-500/mois
1M users: $2000-5000/mois

Comparaison coût (app moyenne)

🎯 Cas d'Usage Recommandés

Choisir Supabase si :

// Application avec données relationnelles complexes
// E-commerce, SaaS, CRM

// Schema PostgreSQL
CREATE TABLE products (
  id UUID PRIMARY KEY DEFAULT uuid_generate_v4(),
  name TEXT NOT NULL,
  price DECIMAL(10,2),
  stock INT
);

CREATE TABLE orders (
  id UUID PRIMARY KEY,
  user_id UUID REFERENCES users(id),
  created_at TIMESTAMP DEFAULT NOW()
);

CREATE TABLE order_items (
  id UUID PRIMARY KEY,
  order_id UUID REFERENCES orders(id),
  product_id UUID REFERENCES products(id),
  quantity INT,
  unit_price DECIMAL(10,2)
);

// Queries SQL puissantes
SELECT
  u.name,
  COUNT(o.id) AS order_count,
  SUM(oi.quantity * oi.unit_price) AS total_spent
FROM users u
LEFT JOIN orders o ON u.id = o.user_id
LEFT JOIN order_items oi ON o.id = oi.order_id
GROUP BY u.id, u.name
ORDER BY total_spent DESC
LIMIT 10;

Choisir Firebase si :

// Application avec données hiérarchiques/documents
// Chat app, social media, real-time collaboration

// Structure Firestore
users/{userId}/
  profile: {...}
  chats/{chatId}/
    messages/{messageId}: {
      text: "Hello",
      timestamp: Timestamp,
      authorId: "user123"
    }

// Real-time updates simples
onSnapshot(doc(db, 'chats', chatId), (snapshot) => {
  updateUI(snapshot.data());
});

🔮 Conclusion

Supabase : idéal pour applications nécessitant SQL, relations complexes, et pricing prévisible. Parfait pour SaaS, e-commerce, CRM.

Firebase : excellent pour prototypage rapide, apps temps réel, et intégration Google Cloud. Idéal pour chat, collaboration, mobile-first.

Recommandation 2025 :

• Nouveau projet SQL → Supabase
• Prototype rapide → Firebase
• Mobile app → Firebase (SDKs matures)
• SaaS B2B → Supabase (RLS, pricing)
• Budget limité → Supabase (plus prévisible)

Les deux plateformes sont excellentes. Le choix dépend de votre modèle de données et cas d'usage spécifiques.

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