Deno

Deploy Hono applications on Deno and Deno Deploy

Deno is a modern, secure runtime for JavaScript and TypeScript. Hono works seamlessly with Deno with full TypeScript support out of the box.

Quick Start

Create a new Hono project for Deno:

deno run -A npm:create-hono@latest my-app

Select “deno” as your template when prompted.

Installation

No installation needed! Import Hono directly from a CDN:

import { Hono } from 'https://deno.land/x/hono/mod.ts'

Or use npm specifiers:

import { Hono } from 'npm:hono@latest'

Basic Usage

Create your application in main.ts:

main.ts

import { Hono } from 'https://deno.land/x/hono/mod.ts'

const app = new Hono()

app.get('/', (c) => c.text('Hello Deno!'))

app.get('/api/hello', (c) => {
  return c.json({ message: 'Hello from Deno!' })
})

Deno.serve(app.fetch)

Deno’s Deno.serve() expects a fetch function. Pass app.fetch directly.

Running Your App

deno run --allow-net main.ts

Or with custom port:

main.ts

import { Hono } from 'https://deno.land/x/hono/mod.ts'

const app = new Hono()

app.get('/', (c) => c.text('Hello Deno!'))

Deno.serve({ port: 3000 }, app.fetch)

Adapter Features

The Deno adapter provides several utilities:

Static Files

Serve static files from a directory:

import { Hono } from 'https://deno.land/x/hono/mod.ts'
import { serveStatic } from 'https://deno.land/x/hono/adapter/deno/index.ts'

const app = new Hono()

app.use('/static/*', serveStatic({ root: './' }))
app.use('/favicon.ico', serveStatic({ path: './favicon.ico' }))

app.get('/', (c) => c.text('Hello!'))

Deno.serve(app.fetch)

WebSocket Support

Upgrade HTTP connections to WebSocket:

import { Hono } from 'https://deno.land/x/hono/mod.ts'
import { upgradeWebSocket } from 'https://deno.land/x/hono/adapter/deno/index.ts'

const app = new Hono()

app.get(
  '/ws',
  upgradeWebSocket((c) => {
    return {
      onMessage(event, ws) {
        console.log(`Message from client: ${event.data}`)
        ws.send('Hello from server!')
      },
      onClose: () => {
        console.log('Connection closed')
      },
    }
  })
)

Deno.serve(app.fetch)

Connection Info

Get connection information including IP address:

import { Hono } from 'https://deno.land/x/hono/mod.ts'
import { getConnInfo } from 'https://deno.land/x/hono/adapter/deno/index.ts'

const app = new Hono()

app.get('/info', (c) => {
  const info = getConnInfo(c)
  return c.json({
    remote: info.remote,
  })
})

Deno.serve(app.fetch)

Static Site Generation (SSG)

Generate static files from your Hono app:

import { Hono } from 'https://deno.land/x/hono/mod.ts'
import { toSSG } from 'https://deno.land/x/hono/adapter/deno/index.ts'

const app = new Hono()

app.get('/', (c) => c.html('<h1>Home</h1>'))
app.get('/about', (c) => c.html('<h1>About</h1>'))

// Generate static files
toSSG(app, { dir: './dist' })

Deno Deploy

Deploy your Hono app to Deno Deploy’s edge network.

1. Create your app

   Create a Hono application:

   main.ts

   import { Hono } from 'https://deno.land/x/hono/mod.ts'
   
   const app = new Hono()
   
   app.get('/', (c) => c.text('Hello Deno Deploy!'))
   
   Deno.serve(app.fetch)
   
2. Deploy with deployctl

   Install and use deployctl:

   deno install -A --no-check -r -f https://deno.land/x/deploy/deployctl.ts
   deployctl deploy --project=my-project main.ts
   
3. Deploy via Git

   Alternatively, connect your Git repository:

   1. Go to Deno Deploy
   2. Click “New Project”
   3. Connect your GitHub repository
   4. Select the entry file (e.g., main.ts)
   5. Deploy

Using Deno KV

Integrate with Deno’s built-in key-value database:

import { Hono } from 'https://deno.land/x/hono/mod.ts'

const app = new Hono()
const kv = await Deno.openKv()

app.get('/kv/:key', async (c) => {
  const key = c.req.param('key')
  const result = await kv.get([key])
  
  if (!result.value) {
    return c.notFound()
  }
  
  return c.json({ value: result.value })
})

app.post('/kv/:key', async (c) => {
  const key = c.req.param('key')
  const body = await c.req.json()
  
  await kv.set([key], body.value)
  
  return c.json({ message: 'Saved' })
})

Deno.serve(app.fetch)

Environment Variables

Access environment variables:

import { Hono } from 'https://deno.land/x/hono/mod.ts'

const app = new Hono()

app.get('/config', (c) => {
  const apiKey = Deno.env.get('API_KEY')
  return c.json({ configured: !!apiKey })
})

Deno.serve(app.fetch)

Run with environment variables:

API_KEY=secret deno run --allow-net --allow-env main.ts

Or use a .env file with a library like dotenv.

Configuration

Create a deno.json configuration file:

deno.json

{
  "tasks": {
    "dev": "deno run --allow-net --allow-read --allow-env --watch main.ts",
    "start": "deno run --allow-net --allow-read --allow-env main.ts"
  },
  "imports": {
    "hono": "https://deno.land/x/hono/mod.ts",
    "hono/": "https://deno.land/x/hono/"
  },
  "compilerOptions": {
    "jsx": "react-jsx",
    "jsxImportSource": "hono/jsx"
  }
}

Run tasks:

deno task dev   # Development with watch mode
deno task start # Production

Using JSX

Hono’s JSX works great with Deno:

import { Hono } from 'https://deno.land/x/hono/mod.ts'
import { jsx } from 'https://deno.land/x/hono/middleware.ts'

const app = new Hono()

app.get('/', (c) => {
  return c.html(
    <html>
      <head>
        <title>Hono + Deno</title>
      </head>
      <body>
        <h1>Hello from Deno!</h1>
      </body>
    </html>
  )
})

Deno.serve(app.fetch)

Best Practices

Use import maps

Define imports in deno.json for cleaner import statements.

Lock dependencies

Use deno.lock to lock dependency versions for reproducible builds.

Minimize permissions

Only grant the permissions your app needs (e.g., --allow-net, --allow-read).

Leverage Deno KV

Use Deno KV for built-in, distributed key-value storage.

Development Features

Watch Mode

Auto-reload on file changes:

deno run --allow-net --watch main.ts

Type Checking

Deno type-checks TypeScript by default. Skip checking for faster startup:

deno run --allow-net --no-check main.ts

Testing

Write tests using Deno’s built-in test runner:

main.test.ts

import { assertEquals } from "https://deno.land/std/assert/mod.ts"
import app from "./main.ts"

Deno.test("GET /", async () => {
  const res = await app.request('http://localhost/')
  assertEquals(res.status, 200)
  assertEquals(await res.text(), 'Hello Deno!')
})

Run tests:

deno test --allow-net

Resources

Deno Manual

Official Deno documentation

Deno Deploy

Deploy to the edge with Deno Deploy