Hello World

The simplest possible NextRush application.

Prerequisites

Node.js 22+ and TypeScript 5.x are required.

The Code

src/index.ts

import { createApp, createRouter, listen } from 'nextrush';

const app = createApp();
const router = createRouter();

router.get('/', (ctx) => {
  ctx.json({ message: 'Hello, NextRush!' });
});

app.route('/', router);

await listen(app, 3000);

Expected output:

curl http://localhost:3000
# {"message":"Hello, NextRush!"}

Step by Step

Create Project

mkdir hello-nextrush && cd hello-nextrush
pnpm init

$ pnpm add nextrush
$ pnpm add -D typescript @types/node

Create tsconfig.json

tsconfig.json

{
  "compilerOptions": {
    "target": "ES2022",
    "module": "NodeNext",
    "moduleResolution": "NodeNext",
    "strict": true,
    "esModuleInterop": true,
    "skipLibCheck": true,
    "outDir": "dist"
  },
  "include": ["src"]
}

Create Entry File

Create src/index.ts with the code from The Code section above.

Run

$ pnpm add -D @nextrush/dev

npx nextrush dev

Test

curl http://localhost:3000
# {"message":"Hello, NextRush!"}

What Each Part Does

createApp()

Creates the NextRush application instance. This manages middleware and plugins.

const app = createApp();

createRouter()

Creates a router for defining routes. NextRush uses a radix tree router.

const router = createRouter();

Route Definition

Define a GET route at the root path:

router.get('/', (ctx) => {
  ctx.json({ message: 'Hello, NextRush!' });
});

ctx — The context object containing request and response
ctx.json() — Send a JSON response

Mounting Routes

Mount the router on the application at a path prefix:

app.route('/', router);

The first argument is the path prefix. All routes defined on the router are served under that prefix.

Starting the Server

Start listening for requests:

await listen(app, 3000);

listen() returns a Promise<ServerInstance>. Use await or handle the promise.

Adding More Routes

Compose multiple routers for different resource groups.

Multi-router composition example (click to expand)

import { createApp, createRouter, listen } from 'nextrush';

const app = createApp();

// Root router
const root = createRouter();
root.get('/', (ctx) => {
  ctx.json({ message: 'Hello, NextRush!' });
});

// Health router
const health = createRouter();
health.get('/', (ctx) => {
  ctx.json({
    status: 'ok',
    uptime: process.uptime(),
  });
});

// Echo router
const echo = createRouter();
echo.get('/', (ctx) => {
  ctx.json({
    method: ctx.method,
    path: ctx.path,
    query: ctx.query,
  });
});

// Users router with parameters
const users = createRouter();
users.get('/:id', (ctx) => {
  ctx.json({ id: ctx.params.id });
});

// Mount all routers
app.route('/', root);
app.route('/health', health);
app.route('/echo', echo);
app.route('/users', users);

await listen(app, 3000);

With Middleware

Add common middleware:

import { createApp, createRouter, listen } from 'nextrush';
import { cors } from '@nextrush/cors';
import { json } from '@nextrush/body-parser';

const app = createApp();

// Middleware (runs before all routes)
app.use(cors());
app.use(json());

// Routes
const api = createRouter();
api.get('/', (ctx) => {
  ctx.json({ message: 'Hello, NextRush!' });
});

api.post('/echo', (ctx) => {
  ctx.json({ received: ctx.body });
});

// Mount
app.route('/api', api);

await listen(app, 3000);

Middleware packages are installed separately.

$ pnpm add @nextrush/cors @nextrush/body-parser

Production Build

# Build for production
npx nextrush build

# Run production build
node dist/index.js

Next Steps

REST API Example — Build a complete CRUD API
Middleware Guide — Learn about middleware
Routing Guide — Deep dive into routing
API Reference — Core — Full Application and Context API
Coming from Express? — Migration guide for Express users

On this page