---
title: Hono middleware
description: Write Hono middleware in Go with the experimental exp/hono package.
sidebar:
  badge: Experimental
---

:::warning[Experimental]
The `exp/hono` package lives under `exp/` and is experimental. Its API is likely to change.
:::

[Hono](https://hono.dev/) is a JavaScript web framework that runs on Workers. `exp/hono` lets you write a Hono **middleware** in Go — the Hono app itself stays in JavaScript, and calls into your Wasm module on each request.

## Write a middleware in Go

A `hono.Middleware` has the signature `func(c *hono.Context, next func())`. Call `next()` to pass control to the next middleware or route handler; work before `next()` runs on the way in, work after it runs on the way out.

```go
import "github.com/syumai/workers-go/exp/hono"

func main() {
	hono.ServeMiddleware(hono.ChainMiddlewares(
		func(c *hono.Context, next func()) {
			c.SetHeader("X-Powered-By", "workers-go")
			next()
		},
	))
}
```

- `hono.ServeMiddleware(m)` registers the middleware and blocks.
- `hono.ChainMiddlewares(m1, m2, ...)` composes several middlewares into one, nesting them in order.

## The Context API

`*hono.Context` wraps the Hono context object:

| Method | Description |
| --- | --- |
| `Request()` | The incoming request as `*http.Request` |
| `SetHeader(key, value)` | Set a response header |
| `SetStatus(code)` | Set the response status code |
| `SetBody(body)` | Replace the response body with an `io.ReadCloser` |
| `ResponseBody()` | Read the response body produced downstream |
| `RawResponse()` | The raw `js.Value` response object |
| `SetResponse(respObj)` | Replace the response with a raw `js.Value` |

## Wire it up in JavaScript

The Wasm module exposes a `runHonoMiddleware` binding. Register it as Hono middleware in your JavaScript entry point so it runs on each request; see the Hono documentation for the middleware API.