Supabase vs Firebase in 2025: The Ultimate BaaS Comparison

The Backend-as-a-Service Landscape

Backend-as-a-Service (BaaS) platforms have revolutionized how developers build applications by abstracting away complex infrastructure management. Supabase and Firebase stand out as two of the most popular options, but they represent fundamentally different philosophies.

In this guide, we'll compare Supabase and Firebase across the key dimensions that matter most to developers and product teams.

Database Architecture & Philosophy

The core difference between these platforms lies in their database architecture:

Firebase:

1. Uses a NoSQL document database (Firestore)
2. Hierarchical data structure with collections and documents
3. Real-time by default
4. Proprietary query language and structure
5. Closed-source platform

Supabase:

1. Built on PostgreSQL (relational database)
2. Standard SQL interface with tables, rows, and columns
3. Real-time capabilities via websockets
4. Uses standard SQL (with PostgreSQL extensions)
5. Open-source platform

This architectural difference affects everything from data modeling to scaling strategies. Firebase's NoSQL approach offers flexibility for rapidly changing schemas, while Supabase's PostgreSQL foundation provides robust data integrity and relationship management.

Data Modeling Comparison

Let's see how the same data model might look in both systems:

Firebase (Firestore) data structure:

// Collection: users
{
  "user123": {
    "name": "John Smith",
    "email": "[email protected]",
    "projects": ["project1", "project2"] // References to project IDs
  }
}
 
// Collection: projects
{
  "project1": {
    "name": "Website Redesign",
    "owner": "user123",
    "tasks": ["task1", "task2"] // References to task IDs
  }
}
 
// Collection: tasks
{
  "task1": {
    "title": "Design Homepage",
    "project": "project1",
    "assignee": "user123",
    "completed": false
  }
}

Supabase (PostgreSQL) data structure:

-- Users table
CREATE TABLE users (
  id UUID PRIMARY KEY DEFAULT uuid_generate_v4(),
  name TEXT NOT NULL,
  email TEXT UNIQUE NOT NULL
);
 
-- Projects table
CREATE TABLE projects (
  id UUID PRIMARY KEY DEFAULT uuid_generate_v4(),
  name TEXT NOT NULL,
  owner_id UUID REFERENCES users(id) ON DELETE CASCADE
);
 
-- Tasks table
CREATE TABLE tasks (
  id UUID PRIMARY KEY DEFAULT uuid_generate_v4(),
  title TEXT NOT NULL,
  project_id UUID REFERENCES projects(id) ON DELETE CASCADE,
  assignee_id UUID REFERENCES users(id) ON DELETE SET NULL,
  completed BOOLEAN DEFAULT false
);

The Supabase model enforces relationships through foreign keys, while Firebase requires manual maintenance of these relationships.

Query Performance

Query performance varies significantly based on the use case:

Firebase strengths:

1. Excels at simple document lookups
2. Fast real-time synchronization
3. Client-side filtering is efficient
4. Scales automatically

Supabase strengths:

1. Complex joins and aggregations
2. Filtering with advanced SQL operators
3. Full-text search capabilities
4. Transaction support

In our benchmarks with a sample app containing 100K records:

For simple reads and real-time updates, Firebase has the edge. For complex queries, Supabase's SQL capabilities provide a significant advantage.

Authentication Systems

Both platforms offer robust authentication systems with different approaches:

Firebase Auth:

1. Handles a wide range of providers (Google, Facebook, Twitter, etc.)
2. Phone number authentication
3. Custom token authentication
4. Email link authentication
5. Built-in UI components

Supabase Auth:

1. Built on PostgreSQL and JWT
2. Supports major OAuth providers
3. Phone authentication (via Twilio integration)
4. Magic link authentication
5. No built-in UI (though community components exist)

Firebase Auth has been around longer and offers more pre-built UI components, while Supabase Auth integrates more seamlessly with your database through PostgreSQL roles and Row Level Security (RLS).

Storage Solutions

Both platforms provide storage solutions for files and media:

Firebase Storage:

1. Based on Google Cloud Storage
2. Focuses on simplicity with automatic scaling
3. Integrated security rules
4. Includes upload/download resumption
5. Progressive uploads for media

Supabase Storage:

1. Built on S3-compatible storage
2. PostgreSQL-based permissions
3. Direct upload from the client
4. CDN integration via custom domains
5. Transformation API for images

Firebase Storage is more mature but Supabase Storage offers tighter integration with database permissions.

Serverless Functions

For custom backend logic, both platforms offer serverless function capabilities:

Firebase Functions:

1. Based on Google Cloud Functions
2. Supports Node.js, Python, Go, Java, Ruby, PHP, and .NET
3. Integrated with other Firebase services
4. Cold starts can impact performance
5. Comprehensive monitoring

Supabase Edge Functions:

1. Built on Deno and deployed on the edge
2. TypeScript/JavaScript support
3. Near-database execution for low latency
4. Limited runtime support compared to Firebase
5. Newer offering with active development

Firebase Functions have greater maturity and language support, while Supabase Edge Functions offer potentially lower latency for database operations.

Real-time Capabilities

Real-time data synchronization is a core feature of both platforms:

Firebase Realtime:

1. Built-in from the beginning
2. Client libraries maintain local state
3. Offline support with sync when reconnected
4. Document-level change notifications
5. Granular security rules for real-time access

Supabase Realtime:

1. Built on PostgreSQL's replication
2. Publication/subscription model
3. Real-time join capabilities
4. Row-level change notifications
5. Broadcast channels for custom events

Firebase's realtime system is more mature and has better offline support, but Supabase's approach allows for real-time joins and leverages PostgreSQL's capabilities.

Pricing Models

Pricing structures differ significantly:

Firebase:

1. Usage-based pricing across all services
2. Generous free tier for development
3. Costs can grow unpredictably with scale
4. Separate pricing for each service (Firestore, Storage, Functions, etc.)

Supabase:

1. Tiered pricing model
2. Free tier with limitations
3. More predictable pricing at scale
4. Single pricing covering all core services

For a typical SaaS application with 10,000 monthly active users, our cost analysis showed:

Supabase generally offers more predictable and often lower pricing, while Firebase's usage-based model can be beneficial for very small applications.

Developer Experience

The developer experience differs substantially:

Firebase:

1. Comprehensive documentation
2. Large ecosystem of tutorials and guides
3. Strong client SDK support across platforms
4. Closely integrated with Google Cloud
5. Mature CLI tools

Supabase:

1. Growing documentation
2. Active Discord community
3. Strong TypeScript support with type generation
4. Open source (can self-host)
5. SQL-first approach familiar to many developers

Both platforms have excellent developer experiences, but Firebase is more beginner-friendly while Supabase appeals to developers with SQL experience.

Client Library Comparison

Let's compare how client code looks for both platforms in a React application:

Firebase Client Example:

// Setting up Firebase
import { initializeApp } from "firebase/app";
import {
  getFirestore,
  collection,
  query,
  where,
  onSnapshot,
} from "firebase/firestore";
 
const firebaseConfig = {
  apiKey: "your-api-key",
  projectId: "your-project-id",
  // ... other config
};
 
const app = initializeApp(firebaseConfig);
const db = getFirestore(app);
 
// React component with real-time query
function TaskList({ projectId }) {
  const [tasks, setTasks] = useState([]);
 
  useEffect(() => {
    const q = query(
      collection(db, "tasks"),
      where("project", "==", projectId),
      where("completed", "==", false)
    );
 
    const unsubscribe = onSnapshot(q, (snapshot) => {
      const taskData = [];
      snapshot.forEach((doc) => {
        taskData.push({ id: doc.id, ...doc.data() });
      });
      setTasks(taskData);
    });
 
    return () => unsubscribe();
  }, [projectId]);
 
  // Render tasks...
}

Supabase Client Example:

// Setting up Supabase
import { createClient } from "@supabase/supabase-js";
 
const supabase = createClient(
  "https://your-project.supabase.co",
  "your-anon-key"
);
 
// React component with real-time query
function TaskList({ projectId }) {
  const [tasks, setTasks] = useState([]);
 
  useEffect(() => {
    // Initial fetch
    const fetchTasks = async () => {
      const { data, error } = await supabase
        .from("tasks")
        .select("*")
        .eq("project_id", projectId)
        .eq("completed", false);
 
      if (!error) setTasks(data);
    };
 
    fetchTasks();
 
    // Set up real-time subscription
    const subscription = supabase
      .channel("public:tasks")
      .on(
        "postgres_changes",
        {
          event: "*",
          schema: "public",
          table: "tasks",
          filter: `project_id=eq.${projectId}`,
        },
        (payload) => {
          // Handle different change types (INSERT, UPDATE, DELETE)
          if (payload.eventType === "INSERT") {
            setTasks((prev) => [...prev, payload.new]);
          } else if (payload.eventType === "UPDATE") {
            setTasks((prev) =>
              prev.map((task) =>
                task.id === payload.new.id ? payload.new : task
              )
            );
          } else if (payload.eventType === "DELETE") {
            setTasks((prev) =>
              prev.filter((task) => task.id !== payload.old.id)
            );
          }
        }
      )
      .subscribe();
 
    return () => {
      subscription.unsubscribe();
    };
  }, [projectId]);
 
  // Render tasks...
}

Both approaches achieve similar results, but Supabase uses SQL-like syntax while Firebase uses a proprietary querying approach.

Security Models

Security implementation differs significantly:

Firebase Security Rules:

1. Custom JSON-based rules language
2. Declarative security model
3. Requires learning Firebase-specific syntax
4. Applied at the document/collection level

// Firebase security rules example
rules_version = '2';
service cloud.firestore {
  match /databases/{database}/documents {
    match /projects/{projectId} {
      allow read: if request.auth != null;
      allow write: if request.auth != null && request.auth.uid == resource.data.owner;
 
      match /tasks/{taskId} {
        allow read: if request.auth != null && get(/databases/$(database)/documents/projects/$(projectId)).data.owner == request.auth.uid;
        allow write: if request.auth != null && get(/databases/$(database)/documents/projects/$(projectId)).data.owner == request.auth.uid;
      }
    }
  }
}

Supabase Row Level Security (RLS):

1. Standard PostgreSQL RLS policies
2. SQL-based security expressions
3. Leverages existing SQL knowledge
4. Applied at the row level with policies

-- Supabase RLS example
-- Enable RLS on the tables
ALTER TABLE projects ENABLE ROW LEVEL SECURITY;
ALTER TABLE tasks ENABLE ROW LEVEL SECURITY;
 
-- Project policies
CREATE POLICY "Users can view their own projects"
ON projects FOR SELECT
USING (auth.uid() = owner_id);
 
CREATE POLICY "Users can create their own projects"
ON projects FOR INSERT
WITH CHECK (auth.uid() = owner_id);
 
-- Task policies
CREATE POLICY "Users can view tasks in their projects"
ON tasks FOR SELECT
USING (
  project_id IN (
    SELECT id FROM projects WHERE owner_id = auth.uid()
  )
);
 
CREATE POLICY "Users can create tasks in their projects"
ON tasks FOR INSERT
WITH CHECK (
  project_id IN (
    SELECT id FROM projects WHERE owner_id = auth.uid()
  )
);

Firebase's security rules can be more intuitive for document-based access patterns, while Supabase's RLS leverages the power of SQL for complex permission scenarios.

Migration Considerations

If you're considering migrating between these platforms:

Firebase to Supabase:

1. Schema transformation from document to relational model
2. Security rules conversion to RLS policies
3. Query rewriting from Firebase SDK to SQL
4. Authentication system transition

Supabase to Firebase:

1. Schema flattening and denormalization
2. RLS policy conversion to security rules
3. Real-time subscription rewrites
4. Authentication reconfiguration

Both migrations require significant effort, with the database structure transformation being the most challenging aspect.

When to Choose Each Platform

Based on our implementation experience with dozens of projects:

Choose Firebase when:

1. You need maximum simplicity for a small team
2. Your data model is document-oriented without complex relationships
3. You want a fully managed service with minimal operational overhead
4. You're building a mobile-first application
5. You're already invested in the Google Cloud ecosystem

Choose Supabase when:

1. Your data has complex relationships that benefit from SQL
2. You have existing SQL expertise on your team
3. You want open-source flexibility with the option to self-host
4. You need predictable pricing at scale
5. You prefer standard technologies over proprietary ones

Conclusion

Firebase and Supabase represent two different philosophies to backend-as-a-service. Firebase offers a fully integrated, proprietary ecosystem that's particularly easy for beginners. Supabase provides an open-source platform built on standard technologies that offers more flexibility for complex applications.

For small to medium projects with simple data requirements, either platform will serve you well. For larger applications with complex data relationships, Supabase's PostgreSQL foundation provides significant advantages. The best choice ultimately depends on your team's expertise, your application's specific requirements, and your scaling plans.