Last Updated: 3/9/2026

Pretty JSON Middleware

Pretty JSON middleware enables “JSON pretty print” for JSON response body. Adding ?pretty to url query param, the JSON strings are prettified.

// GET /
{"project":{"name":"Hono","repository":"https://github.com/honojs/hono"}}

will be:

// GET /?pretty
{
  "project": {
    "name": "Hono",
    "repository": "https://github.com/honojs/hono"
  }
}

Import

import { Hono } from 'hono'
import { prettyJSON } from 'hono/pretty-json'

Usage

const app = new Hono()
 
app.use(prettyJSON()) // With options: prettyJSON({ space: 4 })
app.get('/', (c) => {
  return c.json({ message: 'Hono!' })
})

Options

space: number

Number of spaces for indentation. The default is 2.

query: string

The name of the query string for applying. The default is pretty.

force: boolean

When set to true, JSON responses are always prettified regardless of the query parameter. The default is false.