Backend Template

Todo App Backend Template
REST API

A production-ready REST API Todo backend schema and Starter Kit on Back4app: ER diagram, data dictionary, JSON schema, API playground, code examples, and a one-click AI Agent prompt to deploy in minutes.

Overview

A Todo app is one of the most common starting points for learning backend development. Under the hood it needs user registration, task CRUD, ownership-based access control, and optionally real-time sync.

The schema below defines two classes — _User (built-in) and Todo — connected by a Pointer. With the Back4app REST API SDK, you can interact with this backend from your app — querying, creating, updating, and deleting objects — without writing a custom API layer.

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erDiagram _User { String objectId PK String username String email String password Date createdAt Date updatedAt } Todo { String objectId PK String title Boolean done Date dueDate Number priority Pointer owner FK Date createdAt Date updatedAt } _User ||--o{ Todo : "owns"

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erDiagram
    _User {
        String objectId PK
        String username
        String email
        String password
        Date createdAt
        Date updatedAt
    }

    Todo {
        String objectId PK
        String title
        Boolean done
        Date dueDate
        Number priority
        Pointer owner FK
        Date createdAt
        Date updatedAt
    }

    _User ||--o{ Todo : "owns"

Data Dictionary

Complete field reference for every class in the schema.

Todo

Field	Type	Description	Required
objectId	String	Auto-generated unique identifier	auto
title	String	Short description of the task
done	Boolean	Whether the task is completed	—
dueDate	Date	Optional deadline for the task	—
priority	Number	Priority level (1 = high, 3 = low)	—
owner	Pointer<_User>	User who owns this task	—
createdAt	Date	Auto-generated creation timestamp	auto
updatedAt	Date	Auto-generated last-update timestamp	auto

_User

Field	Type	Description	Required
objectId	String	Auto-generated unique identifier	auto
username	String	Login username
email	String	Email address
password	String	Hashed password (write-only)
createdAt	Date	Auto-generated creation timestamp	auto
updatedAt	Date	Auto-generated last-update timestamp	auto

Schema (JSON)

Raw JSON schema definition — copy and use in your Back4app app or import via the API.

{
  "classes": [
    {
      "className": "Todo",
      "fields": {
        "objectId": {
          "type": "String",
          "required": false
        },
        "title": {
          "type": "String",
          "required": true
        },
        "done": {
          "type": "Boolean",
          "required": false,
          "defaultValue": false
        },
        "dueDate": {
          "type": "Date",
          "required": false
        },
        "priority": {
          "type": "Number",
          "required": false,
          "defaultValue": 3
        },
        "owner": {
          "type": "Pointer",
          "targetClass": "_User",
          "required": false
        },
        "createdAt": {
          "type": "Date",
          "required": false
        },
        "updatedAt": {
          "type": "Date",
          "required": false
        }
      }
    },
    {
      "className": "_User",
      "fields": {
        "objectId": {
          "type": "String",
          "required": false
        },
        "username": {
          "type": "String",
          "required": true
        },
        "email": {
          "type": "String",
          "required": true
        },
        "password": {
          "type": "String",
          "required": true
        },
        "createdAt": {
          "type": "Date",
          "required": false
        },
        "updatedAt": {
          "type": "Date",
          "required": false
        }
      }
    }
  ]
}

Build with AI Agent

Press the button below to open the Agent with this template's prompt pre-filled.

Back4app AI Agent

Ready to build

Create a Todo app on Back4app with this exact schema and behavior.

Schema:
1. _User (use Back4app built-in): username (String, required), email (String, required), password (String, required); objectId, createdAt, updatedAt (system).
2. Todo: title (String, required), done (Boolean, default: false), dueDate (Date, optional), priority (Number, default: 3; 1=high, 2=medium, 3=low), owner (Pointer to _User; set to current user on create); objectId, createdAt, updatedAt (system).

Security:
- Set ACLs on every Todo so only the owner has read and write. No public read/write.
- On create, set Todo.owner to the current user (e.g. via Cloud Code beforeSave or client-side).
- Use Class-Level Permissions so only authenticated users can create/read/update/delete Todo.

Auth:
- Sign-up (username, email, password) and login; support logout/session.
- After login, the app should only show and allow CRUD for the current user's todos.

Behavior:
- Full CRUD for Todo: create, list (only owner's), get one, update (toggle done, edit title, dueDate, priority), delete.
- List todos with sort (e.g. by priority then dueDate or createdAt). Default priority for new todos: 3 (low).

Deliver:
- Create the Back4app app with the schema above, ACLs, and any Cloud Code needed (e.g. beforeSave on Todo to set owner).
- Generate the frontend and connect it to this backend; deploy so the app is runnable end-to-end.

50 free prompts / month — No credit card required

API Playground

Try the REST and GraphQL endpoints for the Todo schema. Responses from the example data above — no Back4app account needed.

GET

https://parseapi.back4app.com/classes/Todo

Headers

{
  "X-Parse-Application-Id": "YOUR_APP_ID",
  "X-Parse-REST-API-Key": "YOUR_REST_API_KEY"
}

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usage.restApi.subtitle

usage.restApi.step1Title

usage.restApi.step1Body

# Required headers for every request
X-Parse-Application-Id: YOUR_APP_ID
X-Parse-REST-API-Key: YOUR_REST_API_KEY

usage.restApi.step2Title

curl -X POST \
  -H "X-Parse-Application-Id: YOUR_APP_ID" \
  -H "X-Parse-REST-API-Key: YOUR_REST_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"title":"Buy groceries","done":false,"priority":2}' \
  https://parseapi.back4app.com/classes/Todo

usage.restApi.step3Title

curl -X GET \
  -H "X-Parse-Application-Id: YOUR_APP_ID" \
  -H "X-Parse-REST-API-Key: YOUR_REST_API_KEY" \
  https://parseapi.back4app.com/classes/Todo

usage.restApi.step4Title

curl -X PUT \
  -H "X-Parse-Application-Id: YOUR_APP_ID" \
  -H "X-Parse-REST-API-Key: YOUR_REST_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"done":true}' \
  https://parseapi.back4app.com/classes/Todo/OBJECT_ID

usage.restApi.step5Title

curl -X DELETE \
  -H "X-Parse-Application-Id: YOUR_APP_ID" \
  -H "X-Parse-REST-API-Key: YOUR_REST_API_KEY" \
  https://parseapi.back4app.com/classes/Todo/OBJECT_ID

Frequently Asked Questions

Common questions about the Todo app backend template.

What is Back4app?

Back4app is the backend behind Todo and task apps. For REST you get clear GET/POST/PUT endpoints for Todo and X-Parse-Session-Token auth—no server to write or host.

Why use Back4app for a Todo REST API?

Back4app exposes a specification-ready REST API for Todo: clear GET/POST/PUT/DELETE endpoints, X-Parse-Session-Token auth, and an API playground. It fits any stack that speaks HTTP and wants a managed BaaS instead of a custom backend.

What is the Todo class in the REST API?

Todo is a Back4app class with title, done, dueDate, priority, and owner (pointer to _User). REST endpoints: GET/POST /classes/Todo, GET/PUT/DELETE /classes/Todo/:id. Responses include objectId, createdAt, updatedAt.

How do I send the session token in REST?

Include the X-Parse-Session-Token header with the value returned at login. The server enforces ACLs so only the owner's todos are returned or modified. Use this header on every authenticated request.

Can I add fields to Todo via the REST API?

Yes. POST or PUT JSON with new fields; Back4app's flexible schema accepts them. Add fields from the dashboard if you prefer. No migrations.

How do I query todos by priority with REST?

Use GET /classes/Todo?where={"priority":1}&order=priority. The where parameter supports comparison operators ($lt, $gt, etc.); order and -order control sort. Use limit and skip for pagination.

Is real-time available for REST clients?

Live Queries use WebSockets and are available for real-time updates. For REST-only clients, poll the GET endpoint or use the REST API for CRUD and a separate subscription mechanism if needed.

How do I add categories or tags via REST?

Add a tags array or a Category class and relation. Send the new fields in POST/PUT bodies. Query with where for filters.

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Todo App Backend TemplateREST API