Supabase vs Firebase in 2026: I Migrated and Here's What Actually Matters#

We spent 18 months building our SaaS on Firebase. Then we migrated to Supabase in 6 weeks.

This isn't a "Firebase bad, Supabase good" post. Both are excellent. But they're fundamentally different, and that difference matters more than any feature comparison.

Here's what I learned migrating a production app with 40K users.

The Core Difference Nobody Talks About#

Firebase is a document database with real-time sync. Supabase is Postgres with a REST API.

Everything else flows from this.

Firebase thinks in documents:

// Firebase
const userDoc = await db.collection('users').doc(userId).get()
const posts = await db.collection('posts')
  .where('userId', '==', userId)
  .get()

Supabase thinks in tables:

// Supabase
const { data: user } = await supabase
  .from('users')
  .select('*')
  .eq('id', userId)
  .single()

const { data: posts } = await supabase
  .from('posts')
  .select('*')
  .eq('user_id', userId)

If you know SQL, Supabase feels natural. If you don't, Firebase is easier to start.

What Supabase Does Better#

1. Joins Are Actually Possible#

Firebase doesn't have joins. You denormalize everything or make multiple queries.

Firebase approach:

// Store user data in every post
{
  id: 'post1',
  title: 'My Post',
  author: {
    id: 'user1',
    name: 'John',
    avatar: 'url'
  }
}

// Problem: When user updates their name, you update every post

Supabase approach:

// Normalized data with joins
const { data: posts } = await supabase
  .from('posts')
  .select(`
    *,
    profiles (
      name,
      avatar_url
    )
  `)

One query. Always up-to-date. No denormalization headaches.

2. Complex Queries Are Simple#

Firebase queries are limited. No OR conditions. No full-text search. No aggregations.

Firebase:

// Can't do: WHERE status = 'published' OR status = 'featured'
// Must do two queries and merge
const published = await db.collection('posts')
  .where('status', '==', 'published')
  .get()

const featured = await db.collection('posts')
  .where('status', '==', 'featured')
  .get()

const combined = [...published.docs, ...featured.docs]

Supabase:

// Just write SQL
const { data } = await supabase
  .from('posts')
  .select('*')
  .or('status.eq.published,status.eq.featured')

// Or use full-text search
const { data } = await supabase
  .from('posts')
  .select('*')
  .textSearch('title', 'nextjs supabase')

If you need complex queries, Supabase wins.

3. Row Level Security Is Built In#

Firebase security rules are powerful but confusing:

// Firebase rules
rules_version = '2';
service cloud.firestore {
  match /databases/{database}/documents {
    match /posts/{postId} {
      allow read: if resource.data.published == true 
                  || resource.data.userId == request.auth.uid;
      allow write: if request.auth.uid == resource.data.userId;
    }
  }
}

Supabase uses Postgres RLS:

-- Supabase RLS
CREATE POLICY "Users can view published posts"
  ON posts FOR SELECT
  USING (published = true OR auth.uid() = user_id);

CREATE POLICY "Users can update own posts"
  ON posts FOR UPDATE
  USING (auth.uid() = user_id);

Both work. But RLS is SQL, so you can test it with regular queries. Firebase rules require the emulator.

4. Migrations Are Version Controlled#

Firebase has no migration system. You change the schema by changing your code.

Supabase has proper migrations:

npx supabase migration new add_posts_table

Every schema change is tracked. You can recreate your database from scratch. You can deploy to multiple environments.

This matters more as your team grows.

5. It's Just Postgres#

Supabase is Postgres with a nice API. That means:

• 30+ years of Postgres tooling works
• You can use any Postgres client
• You can write stored procedures
• You can use triggers
• You can use views
• You can use any Postgres extension

Firebase is proprietary. You're locked into Google's ecosystem.

What Firebase Does Better#

1. Real-Time Is Simpler#

Firebase was built for real-time. It's dead simple:

// Firebase real-time
db.collection('posts')
  .onSnapshot(snapshot => {
    snapshot.docChanges().forEach(change => {
      if (change.type === 'added') {
        console.log('New post:', change.doc.data())
      }
    })
  })

Supabase real-time works, but requires more setup:

// Supabase real-time
// 1. Enable realtime on table
// ALTER PUBLICATION supabase_realtime ADD TABLE posts;

// 2. Subscribe
supabase
  .channel('posts')
  .on('postgres_changes', {
    event: 'INSERT',
    schema: 'public',
    table: 'posts'
  }, payload => {
    console.log('New post:', payload.new)
  })
  .subscribe()

If your app is heavily real-time, Firebase is easier.

2. Offline Support Is Better#

Firebase has excellent offline support. It caches data locally and syncs when online.

Supabase has no built-in offline support. You build it yourself or use a library.

For mobile apps that need offline-first, Firebase wins.

3. Authentication Providers#

Firebase supports more auth providers out of the box:

• Google, Facebook, Twitter, GitHub, Apple
• Phone authentication
• Anonymous authentication
• Custom authentication

Supabase supports:

• Google, GitHub, GitLab, Bitbucket, Azure
• Magic links
• Phone authentication (via Twilio)

Firebase has more options. But Supabase covers the common cases.

4. Ecosystem and Resources#

Firebase has been around since 2011. The ecosystem is massive:

• More tutorials
• More Stack Overflow answers
• More third-party integrations
• More developers who know it

Supabase is newer (2020). The ecosystem is growing fast, but Firebase has more resources.

5. Managed Scaling#

Firebase scales automatically. You don't think about it.

Supabase requires you to choose a plan and upgrade as you grow. You manage database size, connections, and resources.

Firebase is more hands-off. Supabase gives you more control.

The Migration Experience#

Migrating 40K users from Firebase to Supabase took 6 weeks.

Week 1-2: Schema Design

Converted Firebase documents to Postgres tables. Normalized data. Added indexes.

Week 3-4: Data Migration

Wrote scripts to export Firebase data and import to Supabase. Ran in batches to avoid timeouts.

// Migration script
const batch = firestore.collection('posts').limit(1000)
const snapshot = await batch.get()

const posts = snapshot.docs.map(doc => ({
  id: doc.id,
  ...doc.data(),
  created_at: doc.data().createdAt.toDate().toISOString()
}))

await supabase.from('posts').insert(posts)

Week 5: Application Updates

Replaced Firebase SDK with Supabase SDK. Updated queries. Tested everything.

Week 6: Deployment

Deployed new version. Monitored for issues. Fixed bugs.

Biggest challenges:

1. Real-time subscriptions required rewrite
2. Offline support had to be built from scratch
3. Some Firebase-specific features had no Supabase equivalent

Biggest wins:

1. Complex queries became simple
2. Database costs dropped 60%
3. Development velocity increased (SQL is faster than Firestore queries)

When to Choose Firebase#

Choose Firebase if:

• You're building a mobile app with offline-first requirements
• Your app is heavily real-time (chat, collaboration)
• You want fully managed scaling
• You don't know SQL
• You need extensive auth provider support

When to Choose Supabase#

Choose Supabase if:

• You know SQL or want to learn it
• You need complex queries and joins
• You want full control over your database
• You want to avoid vendor lock-in
• You're building a web app with Next.js/React
• You need proper migrations and version control

The Honest Truth#

Both are excellent. The choice depends on your needs:

Firebase is better for:

• Mobile apps
• Real-time apps
• Teams that don't know SQL
• Rapid prototyping

Supabase is better for:

• Web apps
• Complex data models
• Teams that know SQL
• Long-term maintainability

We chose Supabase because:

1. Our team knows SQL
2. We needed complex queries
3. We wanted to avoid vendor lock-in
4. We're building a web app, not mobile

Your needs might be different.

The Bottom Line#

Don't choose based on hype. Choose based on your team's skills and your app's requirements.

If you know SQL and need complex queries, Supabase is amazing. If you need offline-first mobile apps, Firebase is better.

Both will scale. Both are production-ready. Both have great communities.

The best choice is the one that matches your team and your app.

What's your experience with Firebase or Supabase? Drop a comment below.