Why Developers Are Switching from Firebase to Supabase (And You Should Too)

Something shifted in the developer world.

Firebase used to be the default answer to "what backend should I use?" For years, it was the obvious choice — fast setup, real-time database, free tier, backed by Google. Done.

But scroll through any developer community in 2026 — Reddit, X, Discord, Hacker News — and you will see the same pattern: developers are leaving Firebase for Supabase. Not just a few. Thousands.

This is not hype. There are real, practical reasons driving this migration. And if you are still on Firebase, this article will show you exactly why the switch is happening — and how to do it yourself.

The 4 Reasons Developers Are Leaving Firebase

1. The Pricing Time Bomb

This is the number one reason. Every Firebase developer has a horror story.

Firebase charges per document read and write. Sounds fine until your app gets traffic:

Small app (1,000 users):
├── 500K Firestore reads/month  → $0.30
├── 100K Firestore writes/month → $0.18
└── Total: ~$0.50/month         → Feels free!

Growing app (50,000 users):
├── 50M Firestore reads/month   → $30
├── 10M Firestore writes/month  → $18
├── Cloud Functions              → $15
└── Total: ~$63/month           → Getting expensive

Popular app (500,000 users):
├── 500M Firestore reads/month  → $300
├── 100M Firestore writes/month → $180
├── Cloud Functions              → $80
├── Bandwidth                    → $50
└── Total: ~$610/month          → WHERE DID THIS COME FROM?

The problem is not just the cost — it's the unpredictability. A single viral moment, a bot scraping your app, or a poorly optimized query can spike your bill overnight.

Real story: A developer shipped a dashboard that fetched 100 Firestore documents on page load. With 10,000 daily active users, that is 1 million reads per day — 30 million per month — just from one page. The monthly bill jumped from $15 to $180 overnight.

Supabase pricing is flat. $25/month for Pro. Your app can make a billion queries — the price stays the same. You pay for compute and storage, not for how many times your users press a button.

2. NoSQL Hit a Wall

Firestore seemed great when your app was simple. But then you needed to:

• Show a leaderboard → No ORDER BY with LIMIT across collections
• Count total users → No COUNT — you read every document or maintain a counter
• Join user data with orders → No JOINs — you denormalize or make multiple queries
• Search by multiple fields → Requires composite indexes for every combination
• Run analytics → Read every document, aggregate client-side

Here is what a simple "top customers" query looks like in both:

Supabase (PostgreSQL):

SELECT
  users.name,
  COUNT(orders.id) as order_count,
  SUM(orders.total) as total_spent
FROM users
JOIN orders ON users.id = orders.user_id
WHERE orders.created_at > NOW() - INTERVAL '30 days'
GROUP BY users.id
ORDER BY total_spent DESC
LIMIT 10;

One query. One database call. Instant.

Firebase (Firestore):

// Step 1: Get all orders from last 30 days
const ordersSnap = await getDocs(
  query(
    collection(db, 'orders'),
    where('createdAt', '>', thirtyDaysAgo)
  )
);

// Step 2: Group by userId (client-side)
const userTotals = {};
ordersSnap.forEach(doc => {
  const order = doc.data();
  if (!userTotals[order.userId]) {
    userTotals[order.userId] = { count: 0, total: 0 };
  }
  userTotals[order.userId].count++;
  userTotals[order.userId].total += order.total;
});

// Step 3: Sort client-side
const topCustomers = Object.entries(userTotals)
  .sort(([, a], [, b]) => b.total - a.total)
  .slice(0, 10);

// Step 4: Fetch each user's name (N more reads!)
const results = await Promise.all(
  topCustomers.map(async ([userId, stats]) => {
    const userDoc = await getDoc(doc(db, 'users', userId));
    return { name: userDoc.data().name, ...stats };
  })
);

That is potentially thousands of document reads for something PostgreSQL does in one query. And you are paying for every single read.

3. Vendor Lock-In Is Real

With Firebase:

• Your data is in Firestore (proprietary NoSQL format)
• Your auth is in Firebase Auth (Google-only)
• Your functions are Cloud Functions (Google Cloud)
• You cannot self-host any of it
• Exporting data means manually converting documents to another format

If Google changes pricing, deprecates a feature, or you just want to move — you are rewriting your entire backend.

With Supabase:

• Your data is in PostgreSQL — the industry standard
• Export with pg_dump, import anywhere
• Fully open-source — self-host with Docker
• Zero proprietary formats

# Leave Supabase? Take your data with you.
pg_dump -h db.yourproject.supabase.co -U postgres -d postgres > backup.sql

# Restore to any PostgreSQL host
psql -h your-new-host.com -U postgres -d myapp < backup.sql

Supabase is the only major BaaS that is fully open-source. If Supabase disappeared tomorrow, you could self-host everything with Docker and keep building. Try doing that with Firebase.

4. Server-Side Rendering Changed Everything

Firebase was built for a world of client-side SPAs — single-page applications where JavaScript runs in the browser.

But the web moved on. Next.js App Router, Server Components, Server Actions — the future is server-first. And Firebase does not fit.

The Firebase problem with Next.js:

// You need TWO different Firebase SDKs
import { getFirestore } from 'firebase/firestore'        // Client
import { getFirestore } from 'firebase-admin/firestore'  // Server

// Different APIs, different auth contexts, different behavior
// Client SDK uses user tokens, Admin SDK bypasses security rules
// You constantly context-switch between two mental models

Supabase with Next.js:

// One API, works everywhere
import { createClient } from '@/lib/supabase/server'

// Server Component
export default async function Page() {
  const supabase = await createClient()
  const { data } = await supabase.from('posts').select('*')
  return <PostList posts={data} />
}

// Server Action
export async function createPost(formData: FormData) {
  const supabase = await createClient()
  await supabase.from('posts').insert({ title: formData.get('title') })
  revalidatePath('/posts')
}

Same client, same API, same mental model. Supabase's @supabase/ssr package was built for the server-first world.

How to Migrate: Step-by-Step

Ready to switch? Here is the practical migration path.

Step 1: Map Your Firestore Collections to PostgreSQL Tables

Firestore documents become rows. Collections become tables. Nested data gets normalized.

Before (Firestore):

users/
  userId1/
    name: "Alice"
    email: "[e-mail]"
    orders/
      orderId1/
        product: "Widget"
        amount: 29.99
        status: "shipped"

After (PostgreSQL):

CREATE TABLE users (
  id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
  name TEXT NOT NULL,
  email TEXT UNIQUE NOT NULL,
  created_at TIMESTAMPTZ DEFAULT NOW()
);

CREATE TABLE orders (
  id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
  user_id UUID REFERENCES users(id) ON DELETE CASCADE,
  product TEXT NOT NULL,
  amount DECIMAL(10,2) NOT NULL,
  status TEXT DEFAULT 'pending',
  created_at TIMESTAMPTZ DEFAULT NOW()
);

-- Enable RLS
ALTER TABLE users ENABLE ROW LEVEL SECURITY;
ALTER TABLE orders ENABLE ROW LEVEL SECURITY;

CREATE POLICY "Users see own data" ON users
  FOR SELECT USING (auth.uid() = id);

CREATE POLICY "Users see own orders" ON orders
  FOR SELECT USING (auth.uid() = user_id);

Step 2: Migrate Auth Users

Export from Firebase, import to Supabase:

// scripts/migrate-auth.ts
import admin from 'firebase-admin'
import { createClient } from '@supabase/supabase-js'

const firebase = admin.initializeApp({
  credential: admin.credential.cert('./firebase-service-account.json')
})

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

async function migrateUsers() {
  const listResult = await firebase.auth().listUsers(1000)

  for (const user of listResult.users) {
    const { data, error } = await supabase.auth.admin.createUser({
      email: user.email!,
      email_confirm: true,
      user_metadata: {
        name: user.displayName,
        avatar_url: user.photoURL,
        firebase_uid: user.uid // keep reference
      }
    })

    if (error) {
      console.error(`Failed to migrate ${user.email}:`, error.message)
    } else {
      console.log(`Migrated: ${user.email} → ${data.user.id}`)
    }
  }
}

migrateUsers()

Send your users an email before migration: "We are upgrading our infrastructure. You may need to reset your password on your next login." This covers the password hash issue gracefully.

Step 3: Migrate Data

Export Firestore collections to PostgreSQL:

// scripts/migrate-data.ts
import admin from 'firebase-admin'
import { createClient } from '@supabase/supabase-js'

const db = admin.firestore()
const supabase = createClient(
  process.env.SUPABASE_URL!,
  process.env.SUPABASE_SERVICE_ROLE_KEY!
)

async function migrateCollection(
  collectionName: string,
  tableName: string,
  transform: (doc: any) => any
) {
  const snapshot = await db.collection(collectionName).get()
  const rows = snapshot.docs.map(doc => transform({
    firebase_id: doc.id,
    ...doc.data()
  }))

  // Insert in batches of 500
  for (let i = 0; i < rows.length; i += 500) {
    const batch = rows.slice(i, i + 500)
    const { error } = await supabase.from(tableName).insert(batch)

    if (error) {
      console.error(`Batch ${i} failed:`, error.message)
    } else {
      console.log(`Migrated ${Math.min(i + 500, rows.length)}/${rows.length} ${collectionName}`)
    }
  }
}

// Migrate users first (referenced by other tables)
await migrateCollection('users', 'users', (doc) => ({
  id: doc.firebase_id, // or map to new Supabase auth user ID
  name: doc.name,
  email: doc.email,
  created_at: doc.createdAt?.toDate() || new Date()
}))

// Then migrate orders
await migrateCollection('orders', 'orders', (doc) => ({
  user_id: doc.userId, // map to new user ID
  product: doc.product,
  amount: doc.amount,
  status: doc.status,
  created_at: doc.createdAt?.toDate() || new Date()
}))

Step 4: Update Your App Code

Replace Firebase SDK calls with Supabase equivalents:

// BEFORE: Firebase
import { collection, getDocs, addDoc, query, where } from 'firebase/firestore'

const q = query(collection(db, 'tasks'), where('userId', '==', user.uid))
const snapshot = await getDocs(q)
const tasks = snapshot.docs.map(doc => ({ id: doc.id, ...doc.data() }))

await addDoc(collection(db, 'tasks'), {
  title: 'New task',
  userId: user.uid,
  completed: false
})

// AFTER: Supabase
import { createClient } from '@/lib/supabase/server'

const supabase = await createClient()

// RLS handles the user filtering automatically
const { data: tasks } = await supabase
  .from('tasks')
  .select('*')
  .order('created_at', { ascending: false })

await supabase.from('tasks').insert({
  title: 'New task',
  // user_id is set automatically via RLS + auth.uid()
})

Notice how the Supabase version is shorter? You do not need to filter by user ID — Row Level Security handles it automatically. Less code, fewer bugs.

Step 5: Replace Firebase Services

Firebase Service	Supabase Equivalent
Firestore	PostgreSQL database
Firebase Auth	Supabase Auth
Cloud Storage	Supabase Storage
Cloud Functions	Supabase Edge Functions + Next.js Server Actions
Hosting	Vercel (for Next.js)
Realtime Database	Supabase Realtime
Analytics	PostHog or Plausible
Crashlytics	Sentry
Cloud Messaging	OneSignal or Novu

Migration Timeline

For a typical mid-size app:

Week 1:
├── Day 1-2: Set up Supabase project, design PostgreSQL schema
├── Day 3-4: Migrate auth users
└── Day 5: Migrate data

Week 2:
├── Day 1-3: Update app code (replace Firebase SDK with Supabase)
├── Day 4: Test everything
└── Day 5: Deploy + monitor

You do not have to migrate everything at once. Start with new features on Supabase. Migrate existing features one at a time. Run both in parallel until you are confident.

The Results After Switching

Developers who migrated report:

• 60-80% lower monthly costs — flat pricing vs per-read billing
• Faster development — SQL queries replace complex NoSQL workarounds
• Better Next.js integration — first-party SSR support, Server Actions
• Simpler codebase — one API everywhere, RLS handles authorization
• Peace of mind — open source, no vendor lock-in, data portability

Should You Switch?

Switch now if:

• Your Firebase bill is growing faster than your revenue
• You are fighting Firestore's query limitations
• You are building with Next.js (App Router)
• You want data ownership and portability
• You are starting a new project

Stay on Firebase if:

• Your app is deeply integrated with Google Cloud services
• You rely heavily on Firebase Cloud Messaging for push notifications
• Your team has deep Firebase expertise and no SQL experience
• Your app is small, stable, and Firebase costs are negligible

For everyone else — especially if you are building with Next.js — the switch to Supabase is one of the best decisions you will make in 2026.

Ready to start building? Check out our step-by-step tutorial to build a full-stack app with Next.js and Supabase — you will have a working app in 20 minutes.

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Related:

• Build a Full-Stack App with Next.js and Supabase in 20 Minutes
• Supabase vs Firebase in 2026: The Honest Comparison
• Building SaaS with Next.js and Supabase
• Next.js + Supabase Migration Strategies
• Supabase RLS Policy Design Patterns

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Originally published at https://www.iloveblogs.blog