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Supabase Backend as a Service · Lesson

Deploying Your First Function

Write and deploy a simple Edge Function to handle custom API endpoints or backend logic directly from your Supabase project.

Deploying Your First Function is a free Supabase Backend as a Service lesson on CoddyKit — lesson 2 of 4. You can read the complete lesson below for free — then practise it hands-on in the browser with a built-in code editor and a 24/7 AI tutor. It is part of the Supabase Backend as a Service learning path, one of 4 lessons in the course, and your progress syncs across the web and the CoddyKit app.

Making Your Code Go Live

Welcome to deploying your first Supabase Edge Function! This lesson will guide you through taking your function code and making it accessible via an API endpoint.

Deploying means publishing your function so it can be called from your app, a web browser, or other services. It's how your backend logic goes live!

The Supabase CLI

To deploy Edge Functions, you'll primarily use the Supabase Command Line Interface (CLI). This tool helps you manage your Supabase project locally and interact with your remote backend.

  • Ensure the CLI is installed and configured for your project.
  • You'll use commands like supabase functions new and supabase functions deploy.

Creating a New Function

Let's start by creating a new Edge Function. Navigate to your project's root directory in your terminal and use the supabase functions new command:

This command creates a new folder for your function with an index.ts file, which is where your Deno (TypeScript/JavaScript) code will live.

supabase functions new my-first-function

Function Code Structure

After creating the function, you'll find a new directory (e.g., supabase/functions/my-first-function) containing an index.ts file. This file is the entry point for your Edge Function.

Supabase Edge Functions are built on Deno, a secure runtime for JavaScript and TypeScript. They export a default function that handles incoming HTTP requests.

Writing a Simple Function

Now, let's write a basic 'Hello, World!' function. Open the index.ts file inside your new function's directory and replace its content with the following code:

This function simply returns a plain text response. It's a great starting point!

import { serve } from 'https://deno.land/std@0.177.0/http/server.ts'

serve(async (req) => {
  return new Response("Hello from your first Edge Function!", {
    headers: { 'Content-Type': 'text/plain' },
  })
})

Deploying Your Function

With your code ready, it's time to deploy! Use the supabase functions deploy command, specifying your function's name:

The CLI will build your function and upload it to your Supabase project. Once deployed, it becomes a live API endpoint!

supabase functions deploy my-first-function

Invoking with cURL

After deployment, you can test your function. The easiest way is using cURL in your terminal. You'll need your Supabase project URL and your project's Anon Key (found in your project settings).

Replace the placeholders with your actual project details:

curl -X POST 'https://your-project-ref.supabase.co/functions/v1/my-first-function' \
  -H 'Authorization: Bearer YOUR_ANON_KEY' \
  -H 'Content-Type: application/json' \
  -d '{}'

Invoking from Web (JS)

You can also call your Edge Function from any web application using standard fetch API. Here's how you might invoke it from client-side JavaScript:

Remember to replace the placeholder URL and key with your actual project details.

async function callMyFunction() {
  const SUPABASE_URL = "https://your-project-ref.supabase.co";
  const SUPABASE_ANON_KEY = "YOUR_ANON_KEY";

  try {
    const res = await fetch(
      `${SUPABASE_URL}/functions/v1/my-first-function`,
      {
        method: 'POST',
        headers: {
          'Authorization': `Bearer ${SUPABASE_ANON_KEY}`,
          'Content-Type': 'application/json',
        },
        body: JSON.stringify({})
      }
    )
    const data = await res.text() // Use .text() for plain text response
    console.log(data)
  } catch (error) {
    console.error("Error calling function:", error)
  }
}

callMyFunction()

Passing Data & Redeploying

Functions are more useful when they can accept input! Let's update our function to take a name from the request body and respond with a personalized greeting.

After modifying the index.ts file, you'll need to run supabase functions deploy my-first-function again to push the changes live.

import { serve } from 'https://deno.land/std@0.177.0/http/server.ts'

serve(async (req) => {
  const { name } = await req.json() // Expects { "name": "..." }
  const greeting = name ? `Hello, ${name}!` : "Hello there!"

  return new Response(
    JSON.stringify({ message: greeting }),
    { headers: { 'Content-Type': 'application/json' } },
  )
})

Quick Check: Deployment Steps

Which of the following is the correct sequence of steps to deploy a Supabase Edge Function after writing its code?

Recap: Your First Deployment!

You've successfully deployed your first Supabase Edge Function! Here's what we covered:

  • Used the Supabase CLI to manage functions.
  • Created a new function with supabase functions new.
  • Wrote a simple Deno function in index.ts.
  • Deployed it using supabase functions deploy.
  • Invoked the function using cURL and client-side JavaScript.
  • Learned to pass data to functions and redeploy changes.

Now you have a live backend endpoint ready for action!

Frequently asked questions

Is the “Deploying Your First Function” lesson free?

Yes — the full text of “Deploying Your First Function” is free to read here on the web, and the Supabase Backend as a Service course includes 4 lessons in total. To practise it interactively (a built-in code editor and a 24/7 AI tutor) and unlock the rest of the Supabase Backend as a Service course, upgrade to CoddyKit PRO.

What will I learn in “Deploying Your First Function”?

Write and deploy a simple Edge Function to handle custom API endpoints or backend logic directly from your Supabase project. You practise Supabase Backend as a Service with hands-on code you run directly in the browser, and a 24/7 AI tutor answers your questions as you work through the lesson.

Do I need any experience to start Supabase Backend as a Service?

No prior experience is required. Supabase Backend as a Service on CoddyKit is structured for beginners through advanced learners; this is — lesson 2 of 4, so you can start here or from the beginning and move at your own pace.

How long does the “Deploying Your First Function” lesson take?

Most CoddyKit lessons take about 5–10 minutes. Each one is bite-sized and interactive, so you make steady progress and pick up exactly where you left off across the web and the app.

Can I write and run code in this Supabase Backend as a Service lesson?

Yes. Every Supabase Backend as a Service lesson includes a built-in code editor, so you write and run real code right in your browser and get instant AI feedback — no local setup required.

All lessons in this course

  1. Introduction to Edge Functions
  2. Deploying Your First Function
  3. Integrating Functions with Your App
  4. Secrets, Environment Variables, and Scheduled Functions
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