Todo App Backend Template
GraphQL — Schema, API & AI Guide

Key Takeaways

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 GraphQL SDK, you can interact with this backend from your app — querying, creating, updating, and deleting objects — without writing a custom API layer.

Why Build Your Todo GraphQL API with Back4app?

Back4app provides a GraphQL endpoint alongside REST so you can query and mutate with a single endpoint.

• •Single endpoint: POST to the GraphQL endpoint with queries and mutations; request only the fields you need.
• •Typed schema: The Todo and User types are generated from your Back4app schema; use them in your client for type-safe requests.
• •Auth in context: Send the session token in headers; the resolver enforces ownership so responses only include the current user's todos.

Ideal for teams already using GraphQL clients (Apollo, urql) or code generation.

Core Benefits

A production-ready Todo backend so you can ship faster and focus on your app.

Technical Stack

Everything powering this Todo app template at a glance.

ER Diagram

Entity-Relationship diagram for the GraphQL Todo app data model.

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"

Integration Flow

Auth-to-CRUD sequence: how your GraphQL app talks to Back4app — login, then query and create todos.

sequenceDiagram
  participant User
  participant Client as GraphQL Client
  participant Back4app as Back4app Cloud

  User->>Client: Login
  Client->>Back4app: mutation { logIn(username, password) }
  Back4app-->>Client: Session token
  Client-->>User: Logged in

  User->>Client: Load todos
  Client->>Back4app: query { todos { edges { node { objectId title done } } } }
  Back4app-->>Client: Todo list
  Client-->>User: Show list

  User->>Client: Create todo
  Client->>Back4app: mutation { createTodo(input: { ... }) }
  Back4app-->>Client: Todo (objectId)
  Client-->>User: Updated list

Data Dictionary

Complete field reference for every class in the schema.

Security & Permissions

How ownership, ACLs, and class-level permissions protect data in this schema.

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
        }
      }
    }
  ]
}

API Playground

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

Uses the same Todo schema as this template.

Step-by-Step GraphQL Integration

Connect to your Back4app backend from a GraphQL app using the Back4app GraphQL SDK.

1. usage.graphql.step1Title

   usage.graphql.step1Desc

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   query GetTodos {
     todos {
       edges {
         node {
           objectId
           title
           done
           dueDate
           priority
           createdAt
         }
       }
     }
   }

2. usage.graphql.step2Title

   usage.graphql.step2Desc

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   mutation CreateTodo($title: String!, $done: Boolean, $priority: Int) {
     createTodo(input: {
       fields: {
         title: $title
         done: $done
         priority: $priority
       }
     }) {
       todo {
         objectId
         title
         done
         createdAt
       }
     }
   }

3. usage.graphql.step3Title

   usage.graphql.step3Desc

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   mutation UpdateTodo($objectId: ID!, $done: Boolean) {
     updateTodo(input: {
       objectId: $objectId
       fields: { done: $done }
     }) {
       todo { objectId done }
     }
   }
   
   mutation DeleteTodo($objectId: ID!) {
     deleteTodo(input: { objectId: $objectId }) { success }
   }

Frequently Asked Questions

Common questions about the Todo app backend template.