Bun #

Bun is another JavaScript runtime. It’s not Node.js or Deno. Bun includes a trans compiler, so we can write the code with TypeScript.

Hono also works on Bun. Some middleware does not work with Bun, so please keep it in mind.

1. Install #

bun command #

To install bun command, follow the instruction in the official web site.

bun add #

Make the project directory, move into it, and run bun add command to install Hono from npm registry.

bun add hono

2. Hello World #

“Hello World” script is below. Almost the same as writing on other platforms.

import { Hono } from 'hono'

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

export default {
  port: 3000,
  fetch: app.fetch,

3. Run #

Run the command.

bun run index.ts

Then, access http://localhost:3000 in your browser.

bun create #

You can also make a skelton project of Hono by the command below:

bun create hono ./my-app
cd my-app
bun run start

Unsupported Middleware #

Currently, Bun does not support some function for working the application correct with Hono.

  • JWT middleware does not work on Bun yet. DO NOT USE JWT middleware on Bun.

Advanced #

Testing #

You can use bun:test for testing on Bun.

import { describe, expect, it } from 'bun:test'
import app from "."

describe('My first test', () => {
  it('Should return 200 Response', async () => {
    const req = new Request('http://localhost/')
    const res = await app.fetch(req)

Then, run the command.

bun wiptest index.test.ts
wiptest” command is a still WIP. “test” command that is not a WIP might be released.

JSX Middleware #

JSX Middleware works on Bun. It does not depend React, so you can use JSX without installing React. To use it, set up tsconfig.json like below:

  "compilerOptions": {
    "jsx": "react-jsx",
    "jsxFragmentFactory": "Fragment",
    "jsxImportSource": "hono/jsx"
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