Quickstarters
How to Build a Backend for Astro?

21min
Introduction
In this guide on how to build a backend for astro, you’ll learn how to create a complete backend using Back4App for your Astro project. 
We’ll cover integrating important Back4App features, including database management, cloud functions, authentication, file storage, real-time queries, and more—demonstrating a practical approach to building fast applications with modern tooling.
By leveraging Back4App’s environment, you skip a lot of heavy lifting, like configuring servers or writing security layers from scratch. 
This setup saves you time and effort, while still letting you define an endpoint for robust server-side logic. 
You’ll also see how to incorporate environment variables in your astro project, making it easier to store credentials or other sensitive data securely.
Once you finish, you’ll have a scalable backend structure for Astro and know how to handle data with REST, GraphQL, user authentication, real-time events, and more. 
You’ll be prepared to add your own logic for any real-world needs while retaining a strong security foundation.
Prerequisites
A Back4App account and a new Back4App project
Getting Started with Back4app.﻿
An Astro project
Setting up Astro - Ensure you have a basic Astro development environment and Node.js installed.
Node.js (version 14 or above) installed
Installing Node.js﻿
Familiarity with front-end and server-side concepts
You should know how to create or edit .astro files, handle environment variables, and do a simple post request with fetch or a similar library.
Make sure these prerequisites are in place before you begin. Having your Back4App account, an Astro environment, and basic JavaScript knowledge will help you follow along with this tutorial more smoothly.
Step 1 – Creating a New Project on Back4App and connecting
Create a New Project:
Log in to your Back4App account.
Click New App in your Back4App dashboard and give it a name (e.g., “Astro-Backend-Tutorial”).
Retrieve Back4App Credentials:
In your Back4App dashboard, under App Settings or Security & Keys, note your Application ID, REST API Key, and the server URL (https://parseapi.back4app.com by default). These environment variables will be used in your Astro integration.
Connecting Astro to Back4App via APIs:
Since we are not using the Parse SDK directly, we’ll make requests using fetch or another library from our Astro files. Store your credentials in environment variables for security. For example, in a .env file:
Step 2 – Setting Up the Database
Creating a Data model
Manually Create a Data Model:
Go to your Back4App dashboard and click on Database.
Create a new class (e.g., “Todo”), and add fields like title (String) and isCompleted (Boolean).
Use the AI Agent to Create a Data Model:
Open the AI Agent from your app dashboard.
Describe your schema in plain language (e.g., “Create a new ToDo App with a class that has title and isCompleted fields.”).
The agent will generate the class and fields for you.
Reading and Writing Data using REST API
With your data model ready, let’s define an endpoint inside an Astro component or server-side file to handle a post request and a read request. For example, you might create a file like src/pages/api/todos.astro:
Text
---
import type { APIRoute } from 'astro';

export const post: APIRoute = async ({ request }) => {
  const body = await request.json();

  // "create" a Todo
  const url = `${import.meta.env.BACK4APP_SERVER_URL}/classes/Todo`;

  const response = await fetch(url, {
    method: 'POST',
    headers: {
      'X-Parse-Application-Id': import.meta.env.BACK4APP_APP_ID,
      'X-Parse-REST-API-Key': import.meta.env.BACK4APP_REST_KEY,
      'Content-Type': 'application/json'
    },
    body: JSON.stringify({
      title: body.title,
      isCompleted: body.isCompleted
    })
  });

  const data = await response.json();
  return new Response(JSON.stringify(data), { status: 200 });
};

export const get: APIRoute = async () => {
  // "read" all Todos
  const url = `${import.meta.env.BACK4APP_SERVER_URL}/classes/Todo`;

  const response = await fetch(url, {
    method: 'GET',
    headers: {
      'X-Parse-Application-Id': import.meta.env.BACK4APP_APP_ID,
      'X-Parse-REST-API-Key': import.meta.env.BACK4APP_REST_KEY
    }
  });

  const data = await response.json();
  return new Response(JSON.stringify(data), { status: 200 });
};
---

<html lang="en">
  <head>
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <link rel="icon" type="image/svg+xml" href="/favicon.svg" />
    <meta name="generator" content="astro.generator" />
    <title>Todos API</title>
  </head>
  <body>
    <h1>API for Todo</h1>
  </body>
</html>
---
import type { APIRoute } from 'astro';

export const post: APIRoute = async ({ request }) => {
  const body = await request.json();

  // "create" a Todo
  const url = `${import.meta.env.BACK4APP_SERVER_URL}/classes/Todo`;

  const response = await fetch(url, {
    method: 'POST',
    headers: {
      'X-Parse-Application-Id': import.meta.env.BACK4APP_APP_ID,
      'X-Parse-REST-API-Key': import.meta.env.BACK4APP_REST_KEY,
      'Content-Type': 'application/json'
    },
    body: JSON.stringify({
      title: body.title,
      isCompleted: body.isCompleted
    })
  });

  const data = await response.json();
  return new Response(JSON.stringify(data), { status: 200 });
};

export const get: APIRoute = async () => {
  // "read" all Todos
  const url = `${import.meta.env.BACK4APP_SERVER_URL}/classes/Todo`;

  const response = await fetch(url, {
    method: 'GET',
    headers: {
      'X-Parse-Application-Id': import.meta.env.BACK4APP_APP_ID,
      'X-Parse-REST-API-Key': import.meta.env.BACK4APP_REST_KEY
    }
  });

  const data = await response.json();
  return new Response(JSON.stringify(data), { status: 200 });
};
---

<html lang="en">
  <head>
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <link rel="icon" type="image/svg+xml" href="/favicon.svg" />
    <meta name="generator" content="astro.generator" />
    <title>Todos API</title>
  </head>
  <body>
    <h1>API for Todo</h1>
  </body>
</html>
﻿
This example uses environment variables (import.meta.env.*) to store your Back4App credentials. We define two methods in one file: export const post for creating a Todo, and export const get for retrieving all Todos. You can adapt it to suit your layout component structure and other site pages.
Reading and Writing Data using GraphQL API
Similarly, you can perform GraphQL requests from your Astro pages:
Text
---
export async function post({ request }) {
  const body = await request.json();
  const url = `${import.meta.env.BACK4APP_SERVER_URL}/graphql`;

  const query = `
    mutation {
      createTodo(input: {
        fields: {
          title: "${body.title}"
          isCompleted: ${body.isCompleted}
        }
      }) {
        todo {
          objectId
          title
          isCompleted
        }
      }
    }
  `;

  const response = await fetch(url, {
    method: 'POST',
    headers: {
      'X-Parse-Application-Id': import.meta.env.BACK4APP_APP_ID,
      'X-Parse-REST-API-Key': import.meta.env.BACK4APP_REST_KEY,
      'Content-Type': 'application/json'
    },
    body: JSON.stringify({ query })
  });

  const data = await response.json();
  return new Response(JSON.stringify(data), { status: 200 });
}
---
<html lang="en">
  <head>
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <link rel="icon" type="image/svg+xml" href="/favicon.svg" />
    <title>Todos GraphQL</title>
  </head>
  <body>
    <h1>GraphQL Endpoint for Todos</h1>
  </body>
</html>
---
export async function post({ request }) {
  const body = await request.json();
  const url = `${import.meta.env.BACK4APP_SERVER_URL}/graphql`;

  const query = `
    mutation {
      createTodo(input: {
        fields: {
          title: "${body.title}"
          isCompleted: ${body.isCompleted}
        }
      }) {
        todo {
          objectId
          title
          isCompleted
        }
      }
    }
  `;

  const response = await fetch(url, {
    method: 'POST',
    headers: {
      'X-Parse-Application-Id': import.meta.env.BACK4APP_APP_ID,
      'X-Parse-REST-API-Key': import.meta.env.BACK4APP_REST_KEY,
      'Content-Type': 'application/json'
    },
    body: JSON.stringify({ query })
  });

  const data = await response.json();
  return new Response(JSON.stringify(data), { status: 200 });
}
---
<html lang="en">
  <head>
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <link rel="icon" type="image/svg+xml" href="/favicon.svg" />
    <title>Todos GraphQL</title>
  </head>
  <body>
    <h1>GraphQL Endpoint for Todos</h1>
  </body>
</html>
﻿
Working with Live Queries (optional)
Live Queries enable real-time updates to your data. To use them, enable Live Queries in the Back4App dashboard and configure a WebSocket connection. However, if you’re building a static Astro site, you might integrate real-time updates via client-side scripts pointing to wss://YOUR_SUBDOMAIN.b4a.io. Live Queries can push changes to your connected clients whenever records are created, updated, or deleted.
Step 3 – Applying Security with ACLs and CLPs
ACLs (Access Control Lists) and CLPs (Class-Level Permissions) are fundamental to controlling data access. You can configure them in the Database section of your Back4App dashboard. For example:
Restrict read/write to authenticated users only
Use ACLs for per-object security
Use the Back4App Security Guidelines to ensure your data remains protected. You can also set these rules from the dashboard, ensuring that even if your REST calls are open, only correct credentials can modify or view the data.
Step 4 – Writing Cloud Code Functions
Why Cloud Code: You can move key business logic to the server side, avoiding exposure of secrets or the need to maintain separate servers. Cloud Code can listen to triggers (beforeSave, afterSave) or handle custom endpoints.
Example
JS
// main.js (Cloud Code)
Parse.Cloud.define('greetUser', async (request) => {
  const userName = request.params.name || 'Guest';
  return `Hello, ${userName}! Welcome to the Astro project.`;
});

Parse.Cloud.beforeSave('Todo', (request) => {
  const todo = request.object;
  if (!todo.get('title')) {
    throw 'Todos must have a title.';
  }
});
// main.js (Cloud Code)
Parse.Cloud.define('greetUser', async (request) => {
  const userName = request.params.name || 'Guest';
  return `Hello, ${userName}! Welcome to the Astro project.`;
});

Parse.Cloud.beforeSave('Todo', (request) => {
  const todo = request.object;
  if (!todo.get('title')) {
    throw 'Todos must have a title.';
  }
});
﻿
Deploy this via Back4App CLI or directly in the Cloud Code section of your Back4App dashboard.
Calling the Function
From Astro, you can define an endpoint that uses fetch to hit your Cloud Function:
Text
---
export async function post({ request }) {
  const body = await request.json();

  const url = `${import.meta.env.BACK4APP_SERVER_URL}/functions/greetUser`;

  const response = await fetch(url, {
    method: 'POST',
    headers: {
      'X-Parse-Application-Id': import.meta.env.BACK4APP_APP_ID,
      'X-Parse-REST-API-Key': import.meta.env.BACK4APP_REST_KEY,
      'Content-Type': 'application/json'
    },
    body: JSON.stringify({ name: body.name })
  });

  const data = await response.json();
  return new Response(JSON.stringify(data), { status: 200 });
}
---
<html lang="en">
  <head>
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <link rel="icon" type="image/svg+xml" href="/favicon.svg" />
    <title>Cloud Code Greet</title>
  </head>
  <body>
    <h1>Greet Function Endpoint</h1>
  </body>
</html>
---
export async function post({ request }) {
  const body = await request.json();

  const url = `${import.meta.env.BACK4APP_SERVER_URL}/functions/greetUser`;

  const response = await fetch(url, {
    method: 'POST',
    headers: {
      'X-Parse-Application-Id': import.meta.env.BACK4APP_APP_ID,
      'X-Parse-REST-API-Key': import.meta.env.BACK4APP_REST_KEY,
      'Content-Type': 'application/json'
    },
    body: JSON.stringify({ name: body.name })
  });

  const data = await response.json();
  return new Response(JSON.stringify(data), { status: 200 });
}
---
<html lang="en">
  <head>
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <link rel="icon" type="image/svg+xml" href="/favicon.svg" />
    <title>Cloud Code Greet</title>
  </head>
  <body>
    <h1>Greet Function Endpoint</h1>
  </body>
</html>
﻿
Step 5 – Configuring Authentication
Back4App uses the _User class to handle user accounts. With REST, you can manage sign-ups, logins, or logouts. For example, signing up a new user:
Bash
curl -X POST \
  -H "X-Parse-Application-Id: YOUR_APP_ID" \
  -H "X-Parse-REST-API-Key: YOUR_REST_KEY" \
  -H "Content-Type: application/json" \
  -d '{"username":"user1","password":"secret123","email":"[email protected]"}' \
  https://parseapi.back4app.com/users
curl -X POST \
  -H "X-Parse-Application-Id: YOUR_APP_ID" \
  -H "X-Parse-REST-API-Key: YOUR_REST_KEY" \
  -H "Content-Type: application/json" \
  -d '{"username":"user1","password":"secret123","email":"user1@example.com"}' \
  https://parseapi.back4app.com/users
﻿
You can replicate this logic from Astro with fetch in a similar way, using environment variables. Once signed in, the user receives a session token for subsequent requests.
Social Login
For social providers (like Google or Apple), use specific endpoints or set up the OAuth flow. Refer to the Sign in with Apple Docs or other social login guides to integrate advanced authentication. This is particularly useful if you want to let people sign in from your astro project with minimal friction.
Step 6 – Handling File Storage
To store files in Back4App, you send them with the REST API. For instance:
Bash
curl -X POST \
  -H "X-Parse-Application-Id: YOUR_APP_ID" \
  -H "X-Parse-REST-API-Key: YOUR_REST_KEY" \
  -H "Content-Type: image/png" \
  --data-binary "@path/to/local/image.png" \
  https://parseapi.back4app.com/files/myImage.png
curl -X POST \
  -H "X-Parse-Application-Id: YOUR_APP_ID" \
  -H "X-Parse-REST-API-Key: YOUR_REST_KEY" \
  -H "Content-Type: image/png" \
  --data-binary "@path/to/local/image.png" \
  https://parseapi.back4app.com/files/myImage.png
﻿
The response contains a file URL. You can link that URL to a record, like a Photo class object, ensuring you track references to the file in your database. You can also control who can upload by adjusting file security settings in your app configuration.
Step 7 – Email Verification and Password Reset
Enable Email Verification: Under App Settings in the Back4App dashboard, enable email verification and customize your verification email template.
Set up Password Reset: Similarly, configure your password reset emails and ensure the _User class has valid email addresses.
Flow: When a user requests a reset from your astro project (via an API call), Back4App automatically sends an email with a secure link to change their password.
Step 8 – Scheduling Tasks with Cloud Jobs
Use Cloud Jobs to schedule repeated maintenance or other tasks:
JS
// main.js
Parse.Cloud.job('cleanupOldTodos', async () => {
  const query = new Parse.Query('Todo');
  const now = new Date();
  const THIRTY_DAYS = 30 * 24 * 60 * 60 * 1000;
  query.lessThan('createdAt', new Date(now - THIRTY_DAYS));

  const oldTodos = await query.find({ useMasterKey: true });
  await Parse.Object.destroyAll(oldTodos, { useMasterKey: true });
  return `Deleted ${oldTodos.length} old Todos.`;
});
// main.js
Parse.Cloud.job('cleanupOldTodos', async () => {
  const query = new Parse.Query('Todo');
  const now = new Date();
  const THIRTY_DAYS = 30 * 24 * 60 * 60 * 1000;
  query.lessThan('createdAt', new Date(now - THIRTY_DAYS));

  const oldTodos = await query.find({ useMasterKey: true });
  await Parse.Object.destroyAll(oldTodos, { useMasterKey: true });
  return `Deleted ${oldTodos.length} old Todos.`;
});
﻿
Deploy your code, then schedule the job from Server Settings > Background Jobs in the Back4App console. This automates tasks like cleaning data, sending emails, or any routine function you want to run at specific intervals.
Step 9 – Integrating Webhooks
Webhooks let you notify external services when certain events happen in your Back4App app. For example, you can send data to Slack whenever a new Todo is created:
Go to More > WebHooks in your Back4App dashboard.
Add a Webhook pointing to the Slack URL.
Select the event (e.g., object created in the Todo class).
This allows a request/response flow to keep your external systems in sync with your Astro-based application’s data.
Step 10 – Exploring the Back4App Admin Panel
The Back4App Admin App is a user-friendly management panel for data editing. It’s especially useful for non-technical team members who need direct access to your database.
Enable the Admin App under More > Admin App.
Create an admin user for secure access.
Use this panel to quickly perform CRUD operations, check logs, or configure more advanced settings.
Conclusion
You have successfully created a secure and efficient backend for an Astro project using Back4App. Throughout this tutorial, you:
Defined and configured a database schema
Used REST and GraphQL APIs to read and write data
Secured data with ACLs, CLPs, and user authentication
Extended logic through Cloud Code and scheduled jobs
Handled file storage for images or documents
Integrated Webhooks for external notifications
Explored the admin panel for simplified data management
This approach underscores how to build a backend for Astro that is reliable, scalable, and easy to maintain. By leveraging environment variables, you keep your credentials safe while ensuring your code remains flexible for future growth.
Next Steps
Deploy your Astro project with hosting platforms that support server-side rendering or Node-based environments.
Add advanced features, like role-based access control or specialized payment integrations, using Cloud Code or external APIs.
Optimize performance by implementing caching strategies and adjusting your viewport content settings for better user experience.
Review Back4App docs to learn about logs, analytics, and more advanced security measures.
Continue exploring real-time features with Live Queries and build truly dynamic, collaborative applications.
﻿
Updated 15 Jan 2025
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