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Let's start coding the app by defining the Task entity class.

The Task entity class will be used:

  • As a model class for client-side code
  • As a model class for server-side code
  • By remult to generate API endpoints, API queries, and database commands

The Task entity class we're creating will have an auto-generated id field, a title field, a completed field and an auto-generated createdAt field. The entity's API route ("tasks") will include endpoints for all CRUD operations.

Define the Model

  1. Create a shared folder under the src folder. This folder will contain code shared between the frontend and the backend.

  2. Create a file Task.ts in the src/shared/ folder, with the following code:

import { Entity, Fields } from 'remult'

@Entity('tasks', {
  allowApiCrud: true,
export class Task {
  id!: string

  title: string = ''

  completed: boolean = false

  createdAt?: Date

The @Entity decorator tells Remult that this class is an entity class. The decorator accepts a key argument (used to name the API route and as the default database collection/table name), and an optional options object of type EntityOptions. This is used to define entity-related properties and operations, discussed in the next sections of this tutorial.

Initially, we are going to allow all CRUD operations on tasks, by setting the option allowApiCrud to true.

The @Fields.cuid decorator tells Remult to automatically generate a short random id using the cuid library. This value can't be changed after the entity is created.

The @Fields.string decorator tells Remult the title property is an entity data field of type String. This decorator is also used to define field-related properties and operations, discussed in the next sections of this tutorial and the same goes for @Fields.boolean and the completed property.

The @Fields.createdAt decorator tells Remult to automatically generate a createdAt field with the current date and time.


For a complete list of supported field types, see the Field Types section in the Remult documentation.

  1. Register the Task entity with Remult by adding entities: [Task] to the options object that is passed to the remult hook:
import { remultSveltekit } from 'remult/remult-sveltekit'
import { Task } from '../../../shared/Task'

export const handleRemult = remultSveltekit({
  entities: [Task], 

Test the API

Now that the Task entity is defined, we can start using the REST API to query and add tasks. By default Remult exposes the /api/ endpoint. Resources (entities) can then be accessed by appending the entity's key -- tasks in this case.

  1. Open a browser with the url: http://localhost:5173/api/tasks, and you'll see that you get an empty array.

  2. Use curl to POST a new task - Clean car. If you prefer, you can use a graphical tool such as Postman, Insomnia or Thunder Client.

curl http://localhost:5173/api/tasks -d "{\"title\": \"Clean car\"}" -H "Content-Type: application/json"
  1. Refresh the browser for the url: http://localhost:5173/api/tasks and notice that the array now contains one item.

  2. The POST endpoint can accept a single Task or an array of Tasks. Add a few more tasks:

curl http://localhost:5173/api/tasks -d "[{\"title\": \"Read a book\"},{\"title\": \"Take a nap\", \"completed\":true },{\"title\": \"Pay bills\"},{\"title\": \"Do laundry\"}]" -H "Content-Type: application/json"
  1. Refresh the browser again, to see that the new tasks were stored in the db.

Wait, where is the backend database?

While remult supports many relational and non-relational databases, in this tutorial we start off by storing entity data in a backend JSON file. Notice that a db folder has been created under the root folder, with a tasks.json file containing the created tasks.

Display the Task List

Let's start developing the web app by displaying the list of existing tasks.

Let's do it simply in the root of the app by adding this code in +page.svelte:

<script lang="ts">
  import { remult } from "remult";
  import { onMount } from "svelte";
  import { Task } from "../shared/Task";

  let tasks: Task[] = [];

  onMount(async () => {
    tasks = await remult.repo(Task).find();

    {#each tasks as task}
        <input type="checkbox" bind:checked={task.completed} />

Here's a quick overview of the different parts of the code snippet:

  • remult.repo(Task) is a Remult Repository object used to fetch and create Task entity objects.
  • onMount is used to call the Remult repository's find method to fetch tasks from the server, once when the component is loaded.

After the browser refreshes, the list of tasks appears.

Styling the Output

Remult is un-opinionated in as far as front-end styling is concerned. To demonstrate, let's style our app using vanilla CSS.

Simply create these 2 files:

<script lang="ts">
    import "../app.css"

  <title>Remult+Sveltekit Todo App</title>

<slot />
@charset "utf-8";

body {
  font-family: Arial;
  background-color: whitesmoke;
  justify-content: center;
  margin: 0;

h1 {
  color: #ef4444;
  font-style: italic;
  font-size: 3.75rem;
  font-weight: inherit;
  text-align: center;

main {
  max-width: 500px;
  min-width: 300px;
  margin: auto;
  background-color: white;
  box-sizing: border-box;
  border: 1px solid lightgray;
  border-radius: 0.5rem;
    0 2px 4px #0003,
    0 25px 50px #0000001a;

main > div,
main > form {
  padding: 0.5rem 1rem;
  border-bottom: 1px solid lightgray;
  display: flex;
  align-items: center;
  gap: 0.25rem;
  justify-content: space-between;

main > div:has(input[type='checkbox']) {
  justify-content: inherit;

input {
  font-family: inherit;
  font-size: 100%;
  width: 100%;
  border: 0;
  padding: 0.5rem;

input:checked + input,
input:checked + span {
  text-decoration: line-through;

input:placeholder-shown {
  font-style: italic;

input[type='checkbox'] {
  width: 36px;
  height: 36px;
  height: 1.5rem;

button {
  cursor: pointer;
  padding: 0.5rem 0.5rem;
  background-color: white;
  font-family: inherit;
  font-size: 85%;
  line-height: inherit;
  border: 2px solid #0000001a;
  border-radius: 0.5rem;

...and voila!, our app should look much better!! Feel free to improve or substitute the styling as you deem fit.


The styles imported into src/routes/+layout.svelte will apply to all pages in the app - unless explicitly overriden.

MIT Licensed | Made by the Remult team with ❤️