Backend-as-a-Service SDKs Compared: Supabase, Amplify, Firebase, and Parse

When building modern web apps, you often need more than just a UI—you need user accounts, data storage, file uploads, and real-time updates. Instead of building a custom backend, many teams reach for a Backend-as-a-Service (BaaS). The four main contenders—@supabase/supabase-js, aws-amplify, firebase, and parse-server—all promise to simplify this, but they solve the problem in very different ways. Let’s compare them head-to-head based on how you actually use them day-to-day.

🔐 Authentication: Signing In Users

All four support email/password and social logins, but their implementation details vary.

@supabase/supabase-js uses JWTs issued by GoTrue (an open-source identity service). You sign in and get session data immediately.

// Supabase
import { createClient } from '@supabase/supabase-js';
const supabase = createClient('https://...', '...');

const { data, error } = await supabase.auth.signInWithPassword({
  email: 'user@example.com',
  password: 'secret'
});
// data.session contains access_token, user, etc.

aws-amplify wraps AWS Cognito. You configure it once, then use a unified Auth class.

// Amplify
import { Auth } from 'aws-amplify';

try {
  const user = await Auth.signIn('user@example.com', 'secret');
  // user object includes signInUserSession
} catch (error) {
  console.log('Sign in failed', error);
}

firebase uses Firebase Authentication. After init, you call methods directly on the auth instance.

// Firebase
import { getAuth, signInWithEmailAndPassword } from 'firebase/auth';

const auth = getAuth();
try {
  const userCredential = await signInWithEmailAndPassword(auth, 'user@example.com', 'secret');
  // userCredential.user has uid, email, etc.
} catch (error) {
  console.error('Login failed:', error);
}

parse-server handles auth through its REST API. You typically use the Parse SDK’s logIn method.

// Parse
import Parse from 'parse';

try {
  const user = await Parse.User.logIn('user@example.com', 'secret');
  // user is the current logged-in Parse.User
} catch (error) {
  console.error('Login failed:', error.message);
}

💡 Key difference: Supabase and Firebase return user/session objects directly. Amplify abstracts Cognito sessions behind its own interface. Parse relies on a global Parse.User.current() pattern.

🗃️ Data Storage: Reading and Writing Records

How you store and query data is where these SDKs diverge most.

@supabase/supabase-js exposes a fluent API over Postgres tables. You write queries that look like SQL.

// Supabase: relational queries
const { data, error } = await supabase
  .from('posts')
  .select('id, title, author!inner(name)')
  .eq('published', true)
  .order('created_at', { ascending: false });

aws-amplify typically uses GraphQL with AWS AppSync (though REST is possible). You define operations in .graphql files.

// Amplify: GraphQL query
import { API } from 'aws-amplify';
import { listPosts } from './graphql/queries';

const response = await API.graphql({
  query: listPosts,
  variables: { filter: { published: { eq: true } } }
});
// response.data.listPosts.items

firebase uses Firestore (NoSQL). You navigate collections and documents.

// Firebase: Firestore query
import { collection, query, where, orderBy, getDocs } from 'firebase/firestore';

const q = query(
  collection(db, 'posts'),
  where('published', '==', true),
  orderBy('createdAt', 'desc')
);
const snapshot = await getDocs(q);
const posts = snapshot.docs.map(doc => ({ id: doc.id, ...doc.data() }));

parse-server uses a simple object model. Queries are built with a chainable builder.

// Parse
const Post = Parse.Object.extend('Post');
const query = new Parse.Query(Post);
query.equalTo('published', true);
query.descending('createdAt');
const results = await query.find();
// results is an array of Parse.Object instances

💡 Key difference: Supabase gives you SQL power (joins, filters, RLS). Firebase forces denormalization but offers live sync. Amplify leans on GraphQL types. Parse uses a classic ORM-like approach.

🔄 Real-Time Updates: Listening for Changes

Live data is critical for chat apps, dashboards, or collaborative tools.

@supabase/supabase-js uses PostgreSQL’s replication slots to push changes over WebSockets.

// Supabase: real-time subscription
const channel = supabase
  .channel('posts-changes')
  .on(
    'postgres_changes',
    { event: 'INSERT', schema: 'public', table: 'posts' },
    (payload) => console.log('New post:', payload.new)
  )
  .subscribe();

aws-amplify uses AppSync subscriptions over MQTT/WebSockets.

// Amplify: GraphQL subscription
import { graphqlOperation } from 'aws-amplify';
import { onCreatePost } from './graphql/subscriptions';

const subscription = API.graphql(
  graphqlOperation(onCreatePost)
).subscribe({
  next: (data) => console.log('New post:', data.value.data.onCreatePost)
});

firebase has built-in real-time listeners for Firestore.

// Firebase: onSnapshot listener
import { collection, query, where, onSnapshot } from 'firebase/firestore';

const q = query(collection(db, 'posts'), where('published', '==', true));
const unsubscribe = onSnapshot(q, (snapshot) => {
  snapshot.docChanges().forEach(change => {
    if (change.type === 'added') {
      console.log('New post:', change.doc.data());
    }
  });
});

parse-server does not include native real-time support. You must add it yourself via LiveQuery (a separate plugin) or use WebSockets manually.

// Parse: requires enabling LiveQuery server-side
const query = new Parse.Query(Post);
query.subscribe().then(subscription => {
  subscription.on('create', (post) => {
    console.log('New post:', post);
  });
});
// Note: LiveQuery must be configured in parse-server options

⚠️ Warning: Parse’s real-time capability is optional and not enabled by default. The other three include it out of the box.

☁️ Hosting and Vendor Lock-in

Your choice here affects long-term flexibility.

• Supabase: Open-source core. You can self-host or use their cloud. Data lives in Postgres—easy to export.
• Amplify: Tightly coupled to AWS. Migrating away means rebuilding auth, storage, and APIs.
• Firebase: Google Cloud only. Exporting Firestore data requires extra tooling.
• Parse: Fully self-hosted. You control the database (MongoDB or Postgres), but you’re responsible for scaling, backups, and uptime.

📦 File Storage: Uploading Images or Documents

All support file uploads, but with different abstractions.

Supabase uses buckets (like S3) with signed URLs.

// Supabase
const { data, error } = await supabase.storage
  .from('avatars')
  .upload('user123.png', file);

Amplify uses S3 under the hood.

// Amplify
import { Storage } from 'aws-amplify';

await Storage.put('avatars/user123.png', file, {
  contentType: 'image/png'
});

Firebase uses Cloud Storage.

// Firebase
import { ref, uploadBytes } from 'firebase/storage';

const storageRef = ref(storage, 'avatars/user123.png');
await uploadBytes(storageRef, file);

Parse stores files via its REST API, typically backed by GridFS (MongoDB) or local disk.

// Parse
const parseFile = new Parse.File('user123.png', file);
await parseFile.save();
// Returns URL like https://your-parse-server.com/files/appId/user123.png

🧪 Offline Support

• Firebase: Automatic offline persistence for Firestore (enabled with one line).
• Amplify: Supports offline mutations with AppSync (conflict resolution via versioning).
• Supabase: No built-in offline support. You’d need to layer something like RxDB.
• Parse: No official offline support. Community plugins exist but aren’t maintained.

🛑 Deprecation and Maintenance Status

As of 2024:

• @supabase/supabase-js: Actively maintained, v2 is current.
• aws-amplify: Actively maintained by AWS.
• firebase: Actively maintained by Google.
• parse-server: Community-maintained. Not deprecated, but development pace is slower. Suitable for legacy migrations, not recommended for new projects unless you need full control and have DevOps resources.

🆚 Summary Table

💡 Final Recommendation

• Need relational data with real-time and hate vendor lock-in? → Supabase.
• Already deep in AWS and need enterprise-grade auth/storage? → Amplify.
• Building a mobile or collaborative app fast with live sync? → Firebase.
• Maintaining an old Parse.com migration or require full self-hosting? → Parse, but only if you accept the operational overhead.

Don’t pick based on hype—pick based on your team’s skills, cloud strategy, and data model needs.