What is Supabase and Supabase Edge Functions? What's the main use?

Question

Supabase is an open-source backend-as-a-service (BaaS) platform that helps developers build secure, scalable applications quickly. It provides a suite of backend tools—similar to Firebase—but built on open standards like PostgreSQL.

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What Supabase Offers (Core Features):

1. PostgreSQL Database – A powerful, scalable, open-source SQL database.
2. Auth – User authentication and authorization with support for social logins (Google, GitHub, etc.).
3. Realtime – Realtime updates using websockets (e.g., when database rows change).
4. Storage – File storage (images, videos, docs) with access control.
5. Edge Functions – Serverless functions that run close to the user (more below).
6. APIs – Auto-generated REST and GraphQL APIs for your database.
7. Dashboard – A web-based GUI for managing your backend.

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⚡ Supabase Edge Functions

Supabase Edge Functions are serverless functions that you write in JavaScript or TypeScript and deploy to run on Deno (a secure runtime similar to Node.js but more modern).

Main Use of Edge Functions:

They are designed for handling backend logic that shouldn't live directly in the client or the database.

✅ Use Cases Include:

• Custom API endpoints (e.g., payment processing, webhook handling)
• Middleware logic (e.g., verifying tokens, checking user roles)
• Connecting to third-party APIs (e.g., Stripe, Twilio, etc.)
• Running logic on scheduled intervals (e.g., cron jobs)
• Doing something that SQL triggers can’t handle

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Why Use Supabase and Edge Functions Together?

• Use Supabase to handle your core app data and auth.
• Use Edge Functions to handle custom logic securely and efficiently.
• Keep everything in one platform, tightly integrated.

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quick comparison and a simple example to help you understand how Supabase Edge Functions work—especially compared to Firebase Cloud Functions.

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Comparison: Supabase Edge Functions vs Firebase Functions

Feature	Supabase Edge Functions	Firebase Cloud Functions
Runtime	Deno (TypeScript-native)	Node.js
Deployment Time	Fast (\~seconds)	Slower (\~minutes)
Cold Start	Very Low (Deno edge runtime)	Can be noticeable
Region	Edge (closer to user, low latency)	Usually centralized
Language Support	TypeScript, JavaScript	JavaScript, TypeScript
Tied to Backend (DB, Auth)	Yes – deeply integrated with Supabase	Yes – integrated with Firebase
Hosting Model	Serverless, edge-deployed	Serverless, central

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✅ Simple Use Case Example

Scenario:

You want to verify that a user has a valid subscription before letting them access premium content.

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1. In Firebase:

You’d write a cloud function like this (Node.js):

exports.checkSubscription = functions.https.onRequest((req, res) => {
  const userId = req.body.userId;
  // Call Stripe or check Firestore
  // Return access status
});

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2. In Supabase (Edge Function):

// supabase/functions/check-subscription/index.ts

import { serve } from "https://deno.land/std/http/server.ts";

serve(async (req) => {
  const { userId } = await req.json();

  // Call Stripe API, or query your Supabase DB
  const isActive = true; // pretend check

  return new Response(JSON.stringify({
    access: isActive ? "granted" : "denied"
  }), {
    headers: { "Content-Type": "application/json" },
  });
});

➕ Bonus:

You can secure this function by requiring Supabase Auth tokens and decoding them right inside the function.

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How to Deploy (CLI):

supabase functions deploy check-subscription

Then call it from your frontend:

const res = await fetch("/functions/v1/check-subscription", {
  method: "POST",
  headers: { "Authorization": `Bearer ${userToken}` },
  body: JSON.stringify({ userId }),
});

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Comments

nice article

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Interesting read