Quick Start

WARNING

It’s best recommended to start a project with the npm create kita command, as it generates a boilerplate with graceful shutdown, resource monitoring, and other useful features.

First of all, make sure you are using Node.js >= 20.

Kita relies on a lot of newer features and APIs that are not available in older versions.

sh

node -v
# v20.0.0 ✅

Automatic Installation

You can start a new Kita project with a single command:

npm create kita

Currently, you can choose between two templates:

• Kita: A normal backend project using Fastify

• Kita & JSX & Tailwind: A frontend project using Fastify and @kitajs/html

Once done, you should see the newly created folder in your directory.

cd project

Start a development server with:

npm dev

Test it out!

Visit http://localhost:1227/reference in your browser to see the generated OpenAPI documentation.

Read our code recipes for more information on how to customize your project.

Minimal Installation

If you already have an existing project and just want to add Kita, here’s how you can do it in the least intrusive way possible.

1. First, install the necessary dependencies:

Terminal

npm i -D @kitajs/cli @kitajs/ts-plugin
npm i @kitajs/runtime fastify

2. Add the Kita plugin to your tsconfig.json for the best possible experience:

tsconfig.json

{
  "compilerOptions": {
    "plugins": [{ "name": "@kitajs/ts-plugin" }]
  }
}

3. If you’re using VSCode, by default it doesn’t use the TypeScript installed in your node_modules. To do so, create a .vscode/settings.json file and add the following content:

   Refer to the official documentation for more information.

.vscode/settings.json

{
  "typescript.tsdk": "node_modules/typescript/lib",
  "typescript.enablePromptUseWorkspaceTsdk": true
}

4. Update the build scripts in your package.json to run kita build before transpiling the code:

package.json

{
  "scripts": {
    "build": "kita build && tsc",
    "start": "node dist/index.js"
  }
}

5. Add the src/index.ts file with the following content:

src/index.ts

// This is required to be executed before any import or require
globalThis.KITA_PROJECT_ROOT ??= __dirname;

import { Kita } from '@kitajs/runtime'; // [!code focus]
import fastify from 'fastify';

const app = fastify();

app.register(Kita); // [!code focus]

app.listen({ port: 3000 });

If you have a formatter or linter configured that doesn’t handle globalThis.KITA_PROJECT_ROOT ??= __dirname; well at the root of your main file.

We recommend that you move this line to src/prelude.ts and import it into your main file:

src/index.ts

// This is required to be executed before any import or require
globalThis.KITA_PROJECT_ROOT ??= __dirname;
import './prelude'; // [!code ++]

// ...

src/prelude.ts

// This is required to be executed before any import or require
globalThis.KITA_PROJECT_ROOT ??= __dirname; // [!code ++]

5. Create your first route in src/routes/hello.ts:

src/routes/hello.ts

export function get() {
  return { hello: 'world' };
}

6. 🎉

You’re ready to run your server:

npm run build
npm start

Test it out!

Visit http://localhost:3000/reference in your browser to see the documentation.

Read our code recipes for more information on how to customize your project.

TIP

This minimal installation does not include features like resource monitoring and graceful shutdown that are essential for a production server.

Generate a template with the npm kita create command to have a complete project and perform your partial migration from there if necessary.