--- url: 'https://elysiajs.com/quick-start.md' --- # Quick Start Elysia is a TypeScript backend framework with multiple runtime support but optimized for Bun. However, you can use Elysia with other runtimes like Node.js. \ Elysia is optimized for Bun which is a JavaScript runtime that aims to be a drop-in replacement for Node.js. You can install Bun with the command below: ::: code-group ```bash [MacOS/Linux] curl -fsSL https://bun.sh/install | bash ``` ```bash [Windows] powershell -c "irm bun.sh/install.ps1 | iex" ``` ::: \ We recommend starting a new Elysia server using `bun create elysia`, which sets up everything automatically. ```bash bun create elysia app ``` Once done, you should see the folder name `app` in your directory. ```bash cd app ``` Start a development server by: ```bash bun dev ``` Navigate to [localhost:3000](http://localhost:3000), which should greet you with "Hello Elysia". ::: tip Elysia provides a `dev` command to automatically reload your server on file changes. ::: To manually create a new Elysia app, install Elysia as a package: ```typescript bun add elysia bun add -d @types/bun ``` This will install Elysia and Bun type definitions. Create a new file `src/index.ts` and add the following code: ```typescript import { Elysia } from 'elysia' const app = new Elysia() .get('/', () => 'Hello Elysia') .listen(3000) console.log( `🦊 Elysia is running at ${app.server?.hostname}:${app.server?.port}` ) ``` Open your `package.json` file and add the following scripts: ```json { "scripts": { "dev": "bun --watch src/index.ts", "build": "bun build src/index.ts --target bun --outdir ./dist", "start": "NODE_ENV=production bun dist/index.js", "test": "bun test" } } ``` These scripts refer to the different stages of developing an application: * **dev** - Start Elysia in development mode with auto-reload on code change. * **build** - Build the application for production usage. * **start** - Start an Elysia production server. If you are using TypeScript, make sure to create, and update `tsconfig.json` to include `compilerOptions.strict` to `true`: ```json { "compilerOptions": { "strict": true } } ``` Node.js is a JavaScript runtime for server-side applications, the most popular runtime for JavaScript which Elysia supports. You can install Node.js with the command below: ::: code-group ```bash [MacOS] brew install node ``` ```bash [Windows] choco install nodejs ``` ```bash [apt (Linux)] sudo apt install nodejs ``` ```bash [pacman (Arch)] pacman -S nodejs npm ``` ::: ## Setup We recommend using TypeScript for your Node.js project. \ To create a new Elysia app with TypeScript, we recommend installing Elysia with `tsx`: ::: code-group ```bash [bun] bun add elysia @elysiajs/node && \ bun add -d tsx @types/node typescript ``` ```bash [pnpm] # pnpm doesn't install peer dependencies pnpm add elysia @elysiajs/node @sinclair/typebox openapi-types && \ pnpm add -D tsx @types/node typescript ``` ```bash [npm] npm install elysia @elysiajs/node && \ npm install --save-dev tsx @types/node typescript ``` ```bash [yarn] yarn add elysia @elysiajs/node && \ yarn add -D tsx @types/node typescript ``` ::: This will install Elysia, TypeScript, and `tsx`. `tsx` is a CLI that transpiles TypeScript to JavaScript with hot-reload and several more features you'd expect from a modern development environment. Create a new file `src/index.ts` and add the following code: ```typescript import { Elysia } from 'elysia' import { node } from '@elysiajs/node' const app = new Elysia({ adapter: node() }) .get('/', () => 'Hello Elysia') .listen(3000, ({ hostname, port }) => { console.log( `🦊 Elysia is running at ${hostname}:${port}` ) }) ``` Open your `package.json` file and add the following scripts: ```json { "scripts": { "dev": "tsx watch src/index.ts", "build": "tsc src/index.ts --outDir dist", "start": "NODE_ENV=production node dist/index.js" } } ``` These scripts refer to the different stages of developing an application: * **dev** - Start Elysia in development mode with auto-reload on code change. * **build** - Build the application for production usage. * **start** - Start an Elysia production server. Make sure to create `tsconfig.json` ```bash npx tsc --init ``` Don't forget to update `tsconfig.json` to include `compilerOptions.strict` to `true`: ```json { "compilerOptions": { "strict": true } } ``` ::: warning If you use Elysia without TypeScript, you may miss out on some features like auto-completion, advanced type checking, and end-to-end type safety, which are core features of Elysia. ::: To create a new Elysia app with JavaScript, start by installing Elysia: ::: code-group ```bash [bun] bun add elysia @elysiajs/node ``` ```bash [pnpm] # pnpm doesn't install peer dependencies pnpm add elysia @elysiajs/node @sinclair/typebox openapi-types ``` ```bash [npm] npm install elysia @elysiajs/node ``` ```bash [yarn] yarn add elysia @elysiajs/node ``` ::: This will install Elysia. Create a new file `src/index.js` and add the following code: ```javascript import { Elysia } from 'elysia' import { node } from '@elysiajs/node' const app = new Elysia({ adapter: node() }) .get('/', () => 'Hello Elysia') .listen(3000, ({ hostname, port }) => { console.log( `🦊 Elysia is running at ${hostname}:${port}` ) }) ``` Open your `package.json` file and add the following scripts: ```json { "type": "module", "scripts": { "dev": "node src/index.js", "start": "NODE_ENV=production node src/index.js" } } ``` These scripts refer to the different stages of developing an application: * **dev** - Start Elysia in development mode. * **start** - Start an Elysia production server. ::: warning If you use Elysia without TypeScript, you may miss out on some features like auto-completion, advanced type checking, and end-to-end type safety, which are core features of Elysia. ::: Elysia is a WinterTC compliant library, which means if a framework or runtime supports Web Standard Request/Response, it can run Elysia. First, install Elysia with the command below: ::: code-group ```bash [bun] bun install elysia ``` ```bash [pnpm] # pnpm doesn't install peer dependencies pnpm install elysia @sinclair/typebox openapi-types ``` ```bash [npm] npm install elysia ``` ```bash [yarn] yarn add elysia ``` ::: Next, select a runtime that supports Web Standard Request/Response. We have a few recommendations: ### Not on the list? If you are using a custom runtime, you may access `app.fetch` to handle the request and response manually. ```typescript import { Elysia } from 'elysia' const app = new Elysia() .get('/', () => 'Hello Elysia') .listen(3000) export default app.fetch console.log( `🦊 Elysia is running at ${app.server?.hostname}:${app.server?.port}` ) ```