Hello World Example

Let’s kick things off with a simple Hello World app — because every great framework deserves a smooth first dance.

We’ll walk you through the minimal setup to get a TriFrost app running locally.

📦 1. Install TriFrost

First, install the core package using your favorite package manager:

# Bun
bun add @trifrost/core

# NPM
npm install @trifrost/core

# PNPM
pnpm add @trifrost/core

# Yarn
yarn add @trifrost/core

✨ 2. Write Your First App

Create a file, for example, server.ts:

import {App} from '@trifrost/core';

new App()
	.get('/', ctx => ctx.text('Hello TriFrost!'))
	.boot();

import {App} from '@trifrost/core';

new App()
	.get('/', ctx => ctx.text('Hello TriFrost!'))
	.boot();

import {App} from '@trifrost/core';

const app = await new App()
	.get('/', ctx => ctx.text('Hello TriFrost!'))
	.boot();

export default app;

Note: There is a slight difference (hopefully one of the only ones 🥹) between Node/Bun and Workerd.
Workerd expects a global fetch handler (the app handles the fetch handler internally) but we need to export our app using export default app.

What’s happening here?

We create a new TriFrost app.
We define a GET route on / that returns a plain text response.
We call boot() to start the server.

🚀 3. Run It

bun run server.ts

node --require tsx server.ts

Ensure you have tsx installed as a dev dependency for this, if not the case npm install --save-dev tsx

Then head to http://localhost:3000 in your browser. And you should see:

Hello, TriFrost!

Nice and clean.

4. Try Adding More Routes

Expand your app like this:

/* Previous getter */
.get('/about', ctx => ctx.html('<html><body><h1>About page</h1></body></html>'))
.get('/json', ctx => ctx.json({ message: 'Hello, JSON world!' }))
/* Boot */

Restart your server, and now you have:

/about: returns an html page
/json: returns a JSON payload

5. Add a Dev Script

If you want to avoid restarting the server manually every time you make changes, you can run your app in watch mode.

Add a dev script to your package.json:

{
  "scripts": {
    "dev": "bun run --watch ./server.ts"
  }
}

{
  "scripts": {
    "dev": "tsx watch ./server.ts"
  }
}

Now you can simply run:

bun run dev

npm run dev

And your server will automatically restart whenever you make code changes.

Next Steps

Check out Understanding Context to learn how the request/response flow works.
Jump into Routing Basics to explore dynamic routes and parameters.
Explore Middleware Basics to extend your app’s power.

That’s it — you’ve got a running TriFrost app!

Let’s keep building. 💪❄️

TriFrost Docs