NotFoundResponse

Kind: Interface

Source: src/types.ts

You can extend this interface to define a custom c.notFound() Response type.

NotFoundResponse is a type extension point for the response returned by c.notFound(). Extend it through module augmentation to describe the JSON body your application returns for missing routes or resources.

Diagram

mermaid
graph LR
  A[Module augmentation] --> B[NotFoundResponse]
  B --> C[c.notFound()]
  C --> D[Typed not-found response]

Usage

ts
import { Hono } from 'hono'

declare module 'hono' {
  interface NotFoundResponse {
    error: 'NOT_FOUND'
    resource: string
  }
}

const app = new Hono()

app.notFound((c) => {
  return c.json(
    {
      error: 'NOT_FOUND',
      resource: c.req.path,
    },
    404
  )
})

app.get('/posts/:id', (c) => {
  const post = null

  if (!post) {
    return c.notFound()
  }

  return c.json(post)
})

AI Coding Instructions

• Extend NotFoundResponse with module augmentation instead of replacing the interface.
• Keep fields declared on NotFoundResponse aligned with the object returned by the configured not-found handler.
• Return c.notFound() from routes that cannot locate a requested resource.
• Define a shared not-found handler with app.notFound() when the application needs a consistent response body.