Supabase vs Firebase: Understanding the Differences

The Comparison Everyone Makes

When developers discover Supabase, the first question is often "How does it compare to Firebase?" This is natural—Firebase has been the dominant BaaS for years. Understanding the differences helps you choose the right tool and sets expectations for what Supabase can (and can't) do.

Fundamental Philosophy Differences

Firebase: Google's Integrated Ecosystem

Firebase is designed as a tightly integrated suite within Google Cloud:

Proprietary technologies optimized to work together
Seamless integration with other Google services
Managed experience with limited customization
NoSQL-first data model

Supabase: Open Source Building Blocks

Supabase assembles open-source tools around PostgreSQL:

Standard, proven technologies
Self-hosting option with no vendor lock-in
More customization and direct database access
SQL-first with relational data model

Database: The Core Difference

This is the most significant architectural difference.

Firebase Firestore

Collection: users
├── Document: user_abc123
│   ├── name: "Alice"
│   ├── email: "alice@example.com"
│   └── posts (subcollection)
│       └── Document: post_xyz789
│           ├── title: "Hello"
│           └── content: "World"

Characteristics:

Document-based (NoSQL)
Hierarchical data structure
Denormalization encouraged
Limited query capabilities
No joins—data must be structured for access patterns

Supabase PostgreSQL

CREATE TABLE users (
  id uuid PRIMARY KEY,
  name text,
  email text UNIQUE
);

CREATE TABLE posts (
  id uuid PRIMARY KEY,
  user_id uuid REFERENCES users(id),
  title text,
  content text
);

-- Query with join
SELECT users.name, posts.title
FROM posts
JOIN users ON posts.user_id = users.id;

Characteristics:

Relational (SQL)
Normalized data structures
Full SQL query power
Joins, aggregations, window functions
ACID compliance

When Each Approach Shines

Use Case	Better Choice	Why
Simple CRUD apps	Either	Both handle basics well
Complex queries	Supabase	SQL joins and aggregations
Deeply nested data	Firebase	Document model fits naturally
Reporting/Analytics	Supabase	SQL aggregations
Rapid prototyping	Firebase	Less schema planning
Data integrity critical	Supabase	Foreign keys, constraints

Query Capabilities

Firebase Firestore Queries

Firestore queries have specific limitations:

// Allowed: single field inequality
db.collection('posts')
  .where('date', '>', yesterday)
  .orderBy('date')

// NOT allowed: inequality on different field than orderBy
db.collection('posts')
  .where('date', '>', yesterday)
  .orderBy('title') // Error!

// NOT allowed without composite index
db.collection('posts')
  .where('category', '==', 'tech')
  .where('published', '==', true)

Supabase PostgreSQL Queries

SQL has no such limitations:

// Multiple conditions, any order
const { data } = await supabase
  .from('posts')
  .select('*')
  .gt('date', yesterday)
  .eq('category', 'tech')
  .eq('published', true)
  .order('title')

// Complex aggregations
const { data } = await supabase
  .rpc('get_post_stats', { user_id: userId })

// The function can use any SQL
CREATE FUNCTION get_post_stats(user_id uuid)
RETURNS TABLE (month date, post_count bigint) AS $$
  SELECT date_trunc('month', created_at), count(*)
  FROM posts WHERE author_id = user_id
  GROUP BY 1 ORDER BY 1
$$ LANGUAGE sql;

Authentication Comparison

Both platforms offer robust authentication, with some differences:

Firebase Auth

Email/password
Phone authentication
OAuth providers
Anonymous authentication
Custom tokens
Firebase-specific SDKs

Supabase Auth (GoTrue)

Email/password
Magic links (passwordless)
OAuth providers
Phone authentication
SAML/SSO (enterprise)
JWT tokens (standard)

Key Difference: Token Format

Firebase uses custom tokens tied to Firebase SDKs. Supabase uses standard JWTs that work with any JWT library:

// Supabase JWT payload (standard)
{
  "sub": "user-uuid",
  "email": "user@example.com",
  "role": "authenticated",
  "exp": 1234567890
}

This means Supabase tokens can be verified by any backend, not just Supabase services.

Real-time Capabilities

Firebase Realtime Database / Firestore

// Listen to document changes
db.collection('messages')
  .orderBy('timestamp')
  .onSnapshot(snapshot => {
    snapshot.docChanges().forEach(change => {
      if (change.type === 'added') {
        // New message
      }
    })
  })

Automatic offline support
Optimistic updates built-in
Tight SDK integration

Supabase Realtime

// Listen to database changes
supabase
  .channel('messages')
  .on('postgres_changes', {
    event: 'INSERT',
    schema: 'public',
    table: 'messages'
  }, payload => {
    // New message
  })
  .subscribe()

Based on PostgreSQL replication
Broadcast and Presence channels
More explicit subscription model
RLS applies to subscriptions

Storage Comparison

Firebase Cloud Storage

Google Cloud Storage backend
Firebase security rules
Integrated with Firebase Auth
Google CDN

Supabase Storage

S3-compatible backend
RLS policies for access control
Image transformations built-in
CDN integration

Access Control Difference

Firebase uses its own rules language:

// Firebase Storage Rules
rules_version = '2';
service firebase.storage {
  match /b/{bucket}/o {
    match /users/{userId}/{allPaths=**} {
      allow read, write: if request.auth.uid == userId;
    }
  }
}

Supabase uses SQL policies:

-- Supabase Storage Policy
CREATE POLICY "Users can access own files"
ON storage.objects FOR ALL
USING (auth.uid()::text = (storage.foldername(name))[1]);

Serverless Functions

Firebase Cloud Functions

Node.js runtime
Triggered by Firebase events
Integrated billing
Cold start considerations

Supabase Edge Functions

Deno runtime (TypeScript)
HTTP triggered
Geographic distribution
Faster cold starts

// Supabase Edge Function
import { serve } from 'https://deno.land/std@0.168.0/http/server.ts'

serve(async (req) => {
  const { name } = await req.json()
  return new Response(
    JSON.stringify({ message: `Hello ${name}!` }),
    { headers: { 'Content-Type': 'application/json' } }
  )
})

Pricing Models

Firebase

Free tier with limits
Pay-as-you-go scaling
Costs based on: reads, writes, storage, bandwidth
Can be unpredictable at scale

Supabase

Free tier (generous)
Predictable monthly pricing
Based on: database size, bandwidth, MAU
Self-hosting option (your infrastructure costs)

Cost Consideration

Firebase's per-operation pricing can surprise you:

Heavy read applications can become expensive
Real-time listeners count as reads
Denormalized data means duplicate reads

Supabase's bandwidth-based pricing is more predictable but:

Large data transfers add up
Database size limits per tier
Egress costs for heavy API usage

Vendor Lock-in

Firebase

Proprietary data format
Export requires transformation
Rules language doesn't transfer
Deep Google ecosystem integration

Supabase

Standard PostgreSQL
pg_dump for full export
SQL skills transfer everywhere
Self-host anytime

# Export Supabase data
pg_dump -h your-project.supabase.co \
        -U postgres \
        -d postgres \
        > backup.sql

# Import anywhere PostgreSQL runs
psql -h new-host -d newdb < backup.sql

Summary Comparison Table

Aspect	Firebase	Supabase
Database	NoSQL (Firestore)	PostgreSQL (SQL)
Open Source	No	Yes
Self-hosting	No	Yes
Query Power	Limited	Full SQL
Data Model	Document	Relational
Auth Tokens	Proprietary	Standard JWT
Functions Runtime	Node.js	Deno
Offline Support	Built-in	Manual
Vendor Lock-in	High	Low
Maturity	10+ years	4+ years
Learning Curve	Lower initially	SQL knowledge helps

Making the Choice

Choose Firebase When:

Your team knows Firebase well
You need excellent offline-first support
Your data is naturally hierarchical
You're building mobile-first applications
You want maximum managed experience

Choose Supabase When:

You value open source and portability
Your data is relational
You need complex queries
SQL expertise exists on your team
You might need to self-host
You want predictable pricing

Key Takeaways

Different databases, different paradigms: NoSQL vs SQL is the core difference
Neither is universally better: The right choice depends on your use case
Lock-in matters: Consider your exit strategy
Query needs vary: Complex reporting favors Supabase
Team skills matter: Use what your team knows or wants to learn

The Firebase vs Supabase debate isn't about which is better—it's about which fits your specific needs. Understanding both helps you make informed decisions.

Supabase vs Firebase: Understanding the Differences

The Comparison Everyone Makes

Fundamental Philosophy Differences

Firebase: Google's Integrated Ecosystem

Firebase is designed as a tightly integrated suite within Google Cloud:

Proprietary technologies optimized to work together
Seamless integration with other Google services
Managed experience with limited customization
NoSQL-first data model

Supabase: Open Source Building Blocks

Supabase assembles open-source tools around PostgreSQL:

Standard, proven technologies
Self-hosting option with no vendor lock-in
More customization and direct database access
SQL-first with relational data model

Database: The Core Difference

This is the most significant architectural difference.

Firebase Firestore

Collection: users
├── Document: user_abc123
│   ├── name: "Alice"
│   ├── email: "alice@example.com"
│   └── posts (subcollection)
│       └── Document: post_xyz789
│           ├── title: "Hello"
│           └── content: "World"

Characteristics:

Document-based (NoSQL)
Hierarchical data structure
Denormalization encouraged
Limited query capabilities
No joins—data must be structured for access patterns

Supabase PostgreSQL

CREATE TABLE users (
  id uuid PRIMARY KEY,
  name text,
  email text UNIQUE
);

CREATE TABLE posts (
  id uuid PRIMARY KEY,
  user_id uuid REFERENCES users(id),
  title text,
  content text
);

-- Query with join
SELECT users.name, posts.title
FROM posts
JOIN users ON posts.user_id = users.id;

Characteristics:

Relational (SQL)
Normalized data structures
Full SQL query power
Joins, aggregations, window functions
ACID compliance

When Each Approach Shines

Use Case	Better Choice	Why
Simple CRUD apps	Either	Both handle basics well
Complex queries	Supabase	SQL joins and aggregations
Deeply nested data	Firebase	Document model fits naturally
Reporting/Analytics	Supabase	SQL aggregations
Rapid prototyping	Firebase	Less schema planning
Data integrity critical	Supabase	Foreign keys, constraints

Query Capabilities

Firebase Firestore Queries

Firestore queries have specific limitations:

// Allowed: single field inequality
db.collection('posts')
  .where('date', '>', yesterday)
  .orderBy('date')

// NOT allowed: inequality on different field than orderBy
db.collection('posts')
  .where('date', '>', yesterday)
  .orderBy('title') // Error!

// NOT allowed without composite index
db.collection('posts')
  .where('category', '==', 'tech')
  .where('published', '==', true)

Supabase PostgreSQL Queries

SQL has no such limitations:

// Multiple conditions, any order
const { data } = await supabase
  .from('posts')
  .select('*')
  .gt('date', yesterday)
  .eq('category', 'tech')
  .eq('published', true)
  .order('title')

// Complex aggregations
const { data } = await supabase
  .rpc('get_post_stats', { user_id: userId })

// The function can use any SQL
CREATE FUNCTION get_post_stats(user_id uuid)
RETURNS TABLE (month date, post_count bigint) AS $$
  SELECT date_trunc('month', created_at), count(*)
  FROM posts WHERE author_id = user_id
  GROUP BY 1 ORDER BY 1
$$ LANGUAGE sql;

Authentication Comparison

Both platforms offer robust authentication, with some differences:

Firebase Auth

Email/password
Phone authentication
OAuth providers
Anonymous authentication
Custom tokens
Firebase-specific SDKs

Supabase Auth (GoTrue)

Email/password
Magic links (passwordless)
OAuth providers
Phone authentication
SAML/SSO (enterprise)
JWT tokens (standard)

Key Difference: Token Format

Firebase uses custom tokens tied to Firebase SDKs. Supabase uses standard JWTs that work with any JWT library:

// Supabase JWT payload (standard)
{
  "sub": "user-uuid",
  "email": "user@example.com",
  "role": "authenticated",
  "exp": 1234567890
}

This means Supabase tokens can be verified by any backend, not just Supabase services.

Real-time Capabilities

Firebase Realtime Database / Firestore

// Listen to document changes
db.collection('messages')
  .orderBy('timestamp')
  .onSnapshot(snapshot => {
    snapshot.docChanges().forEach(change => {
      if (change.type === 'added') {
        // New message
      }
    })
  })

Automatic offline support
Optimistic updates built-in
Tight SDK integration

Supabase Realtime

// Listen to database changes
supabase
  .channel('messages')
  .on('postgres_changes', {
    event: 'INSERT',
    schema: 'public',
    table: 'messages'
  }, payload => {
    // New message
  })
  .subscribe()

Based on PostgreSQL replication
Broadcast and Presence channels
More explicit subscription model
RLS applies to subscriptions

Storage Comparison

Firebase Cloud Storage

Google Cloud Storage backend
Firebase security rules
Integrated with Firebase Auth
Google CDN

Supabase Storage

S3-compatible backend
RLS policies for access control
Image transformations built-in
CDN integration

Access Control Difference

Firebase uses its own rules language:

// Firebase Storage Rules
rules_version = '2';
service firebase.storage {
  match /b/{bucket}/o {
    match /users/{userId}/{allPaths=**} {
      allow read, write: if request.auth.uid == userId;
    }
  }
}

Supabase uses SQL policies:

-- Supabase Storage Policy
CREATE POLICY "Users can access own files"
ON storage.objects FOR ALL
USING (auth.uid()::text = (storage.foldername(name))[1]);

Serverless Functions

Firebase Cloud Functions

Node.js runtime
Triggered by Firebase events
Integrated billing
Cold start considerations

Supabase Edge Functions

Deno runtime (TypeScript)
HTTP triggered
Geographic distribution
Faster cold starts

// Supabase Edge Function
import { serve } from 'https://deno.land/std@0.168.0/http/server.ts'

serve(async (req) => {
  const { name } = await req.json()
  return new Response(
    JSON.stringify({ message: `Hello ${name}!` }),
    { headers: { 'Content-Type': 'application/json' } }
  )
})

Pricing Models

Firebase

Free tier with limits
Pay-as-you-go scaling
Costs based on: reads, writes, storage, bandwidth
Can be unpredictable at scale

Supabase

Free tier (generous)
Predictable monthly pricing
Based on: database size, bandwidth, MAU
Self-hosting option (your infrastructure costs)

Cost Consideration

Firebase's per-operation pricing can surprise you:

Heavy read applications can become expensive
Real-time listeners count as reads
Denormalized data means duplicate reads

Supabase's bandwidth-based pricing is more predictable but:

Large data transfers add up
Database size limits per tier
Egress costs for heavy API usage

Vendor Lock-in

Firebase

Proprietary data format
Export requires transformation
Rules language doesn't transfer
Deep Google ecosystem integration

Supabase

Standard PostgreSQL
pg_dump for full export
SQL skills transfer everywhere
Self-host anytime

# Export Supabase data
pg_dump -h your-project.supabase.co \
        -U postgres \
        -d postgres \
        > backup.sql

# Import anywhere PostgreSQL runs
psql -h new-host -d newdb < backup.sql

Summary Comparison Table

Aspect	Firebase	Supabase
Database	NoSQL (Firestore)	PostgreSQL (SQL)
Open Source	No	Yes
Self-hosting	No	Yes
Query Power	Limited	Full SQL
Data Model	Document	Relational
Auth Tokens	Proprietary	Standard JWT
Functions Runtime	Node.js	Deno
Offline Support	Built-in	Manual
Vendor Lock-in	High	Low
Maturity	10+ years	4+ years
Learning Curve	Lower initially	SQL knowledge helps

Making the Choice

Choose Firebase When:

Your team knows Firebase well
You need excellent offline-first support
Your data is naturally hierarchical
You're building mobile-first applications
You want maximum managed experience

Choose Supabase When:

You value open source and portability
Your data is relational
You need complex queries
SQL expertise exists on your team
You might need to self-host
You want predictable pricing

Key Takeaways

Different databases, different paradigms: NoSQL vs SQL is the core difference
Neither is universally better: The right choice depends on your use case
Lock-in matters: Consider your exit strategy
Query needs vary: Complex reporting favors Supabase
Team skills matter: Use what your team knows or wants to learn

The Firebase vs Supabase debate isn't about which is better—it's about which fits your specific needs. Understanding both helps you make informed decisions.