---
id: whats_new
title: 🆕 Whats New in v3
sidebar_position: 2
toc_max_heading_level: 3
---

:::caution

Its a draft, not finished yet.

:::

[//]: # (https://github.com/gofiber/fiber/releases/tag/v3.0.0-beta.2)

## 🎉 Welcome

We are excited to announce the release of Fiber v3! 🚀

In this guide, we'll walk you through the most important changes in Fiber `v3` and show you how to migrate your existing Fiber `v2` applications to Fiber `v3`.

Here's a quick overview of the changes in Fiber `v3`:
- [🚀 App](#-app)
- [🗺️ Router](#-router)
- [🧠 Context](#-context)
- [📎 Binding](#-binding)
- [🔄️ Redirect](#-redirect)
- [🌎 Client package](#-client-package)
- [🧰 Generic functions](#-generic-functions)
- [🧬 Middlewares](#-middlewares)
  - [CORS](#cors)
  - [Session](#session)
  - [Filesystem](#filesystem)
  - [Monitor](#monitor)
- [📋 Migration guide](#-migration-guide)

## Drop for old Go versions

Fiber `v3` drops support for Go versions below `1.21`. We recommend upgrading to Go `1.21` or higher to use Fiber `v3`.

## 🚀 App

:::caution
DRAFT section
:::

We have made several changes to the Fiber app, including:

* Listen -> unified with config
* app.Config properties moved to listen config
  * DisableStartupMessage
  * EnablePrefork -> previously Prefork
  * EnablePrintRoutes
  * ListenerNetwork -> previously Network

### new methods

* RegisterCustomBinder
* RegisterCustomConstraint
* NewCtxFunc

### removed methods

* Mount -> Use app.Use() instead
* ListenTLS -> Use app.Listen() with tls.Config
* ListenTLSWithCertificate -> Use app.Listen() with tls.Config
* ListenMutualTLS -> Use app.Listen() with tls.Config
* ListenMutualTLSWithCertificate -> Use app.Listen() with tls.Config

### Methods changes

* Test -> timeout changed to 1 second
* Listen -> has a config parameter
* Listener -> has a config parameter

### CTX interface + customizable

---

## 🗺 Router

We have slightly adapted our router interface

### HTTP method registration

In `v2` one handler was already mandatory when the route has been registered, but this was checked at runtime and was not correctly reflected in the signature, this has now been changed in `v3` to make it more explicit.

```diff
-    Get(path string, handlers ...Handler) Router
+    Get(path string, handler Handler, middleware ...Handler) Router
-    Head(path string, handlers ...Handler) Router
+    Head(path string, handler Handler, middleware ...Handler) Router
-    Post(path string, handlers ...Handler) Router
+    Post(path string, handler Handler, middleware ...Handler) Router
-    Put(path string, handlers ...Handler) Router
+    Put(path string, handler Handler, middleware ...Handler) Router
-    Delete(path string, handlers ...Handler) Router
+    Delete(path string, handler Handler, middleware ...Handler) Router
-    Connect(path string, handlers ...Handler) Router
+    Connect(path string, handler Handler, middleware ...Handler) Router
-    Options(path string, handlers ...Handler) Router
+    Options(path string, handler Handler, middleware ...Handler) Router
-    Trace(path string, handlers ...Handler) Router
+    Trace(path string, handler Handler, middleware ...Handler) Router
-    Patch(path string, handlers ...Handler) Router
+    Patch(path string, handler Handler, middleware ...Handler) Router
-    All(path string, handlers ...Handler) Router
+    All(path string, handler Handler, middleware ...Handler) Router
```

### Route chaining

The route method is now like [`Express`](https://expressjs.com/de/api.html#app.route) which gives you the option of a different notation and allows you to concatenate the route declaration.

```diff
-    Route(prefix string, fn func(router Router), name ...string) Router
+    Route(path string) Register    
```

<details>
<summary>Example</summary>

```go
app.Route("/api").Route("/user/:id?")
  .Get(func(c fiber.Ctx) error {
    // Get user
    return c.JSON(fiber.Map{"message": "Get user", "id": c.Params("id")})
  })
  .Post(func(c fiber.Ctx) error {
    // Create user
    return c.JSON(fiber.Map{"message": "User created"})
  })
  .Put(func(c fiber.Ctx) error {
    // Update user
    return c.JSON(fiber.Map{"message": "User updated", "id": c.Params("id")})
  })
  .Delete(func(c fiber.Ctx) error {
    // Delete user
    return c.JSON(fiber.Map{"message": "User deleted", "id": c.Params("id")})
  })
})
```
</details>

[Here](./api/app#route) you can find more information.

### Middleware registration

We have aligned our method for middlewares closer to [`Express`](https://expressjs.com/de/api.html#app.use) and now also support the [`Use`](./api/app#use) of multiple prefixes.

Registering a subapp is now also possible via the [`Use`](./api/app#use) method instead of the old `app.Mount` method.

<details>
<summary>Example</summary>

```go
// register mulitple prefixes
app.Use(["/v1", "/v2"], func(c *fiber.Ctx) error {
  // Middleware for /v1 and /v2
  return c.Next() 
})

// define subapp
api := fiber.New()
api.Get("/user", func(c *fiber.Ctx) error {
  return c.SendString("User")
})
// register subapp
app.Use("/api", api)
```
</details>

To enable the routing changes above we had to slightly adjust the signature of the `Add` method.

```diff
-    Add(method, path string, handlers ...Handler) Router
+    Add(methods []string, path string, handler Handler, middleware ...Handler) Router
```

---

## 🧠 Context

:::caution
DRAFT section
:::


### new methods

* AutoFormat -> ExpressJs like
* Host -> ExpressJs like
* Port -> ExpressJs like
* IsProxyTrusted
* Reset
* Schema -> ExpressJs like
* SendStream -> ExpressJs like
* SendString -> ExpressJs like
* String -> ExpressJs like
* ViewBind -> instead of Bind

### removed methods

* AllParams -> c.Bind().URL() ?
* ParamsInt -> Params Generic
* QueryBool -> Query Generic
* QueryFloat -> Query Generic
* QueryInt -> Query Generic
* BodyParser -> c.Bind().Body()
* CookieParser -> c.Bind().Cookie()
* ParamsParser -> c.Bind().URL()
* RedirectToRoute -> c.Redirect().Route()
* RedirectBack -> c.Redirect().Back()
* ReqHeaderParser -> c.Bind().Header()

### changed methods

* Bind -> for Binding instead of View, us c.ViewBind()
* Format -> Param: body interface{} -> handlers ...ResFmt
* Redirect -> c.Redirect().To()

---

## 🌎 Client package

:::caution
DRAFT section
:::

## 📎 Binding

:::caution
DRAFT section
:::

## 🔄 Redirect

:::caution
DRAFT section
:::


## 🧰 Generic functions

:::caution
DRAFT section
:::

## 🧬 Middlewares

### CORS

We've made some changes to the CORS middleware to improve its functionality and flexibility. Here's what's new:

#### New Struct Fields
- `Config.AllowPrivateNetwork`: This new field is a boolean that allows you to control whether private networks are allowed. This is related to the [Private Network Access (PNA)](https://wicg.github.io/private-network-access/) specification from the Web Incubator Community Group (WICG). When set to `true`, the CORS middleware will allow CORS preflight requests from private networks and respond with the `Access-Control-Allow-Private-Network: true` header. This could be useful in development environments or specific use cases, but should be done with caution due to potential security risks.

#### Updated Struct Fields
We've updated several fields from a single string (containing comma-separated values) to slices, allowing for more explicit declaration of multiple values. Here are the updated fields:

- `Config.AllowOrigins`: Now accepts a slice of strings, each representing an allowed origin.
- `Config.AllowMethods`: Now accepts a slice of strings, each representing an allowed method.
- `Config.AllowHeaders`: Now accepts a slice of strings, each representing an allowed header.
- `Config.ExposeHeaders`: Now accepts a slice of strings, each representing an exposed header.

### Session

:::caution
DRAFT section
:::

### Filesystem

:::caution
DRAFT section
:::

### Monitor

:::caution
DRAFT section
:::

Monitor middleware is now in Contrib package.

## 📋 Migration guide

- [🚀 App](#-app-1)
- [🗺 Router](#-router-1)
- [🧠 Context](#-context-1)
- [📎 Parser](#-parser)
- [🔄 Redirect](#-redirect-1)
- [🌎 Client package](#-client-package-1)
- [🧬 Middlewares](#-middlewares-1)


### 🚀 App

### 🗺 Router

### 🧠 Context

### 📎 Parser

### 🔄 Redirect

### 🌎 Client package

### 🧬 Middlewares

#### CORS

The CORS middleware has been updated to use slices instead of strings for the `AllowOrigins`, `AllowMethods`, `AllowHeaders`, and `ExposeHeaders` fields. Here's how you can update your code:

```go
// Before
app.Use(cors.New(cors.Config{
  AllowOrigins: "https://example.com,https://example2.com",
  AllowMethods: strings.Join([]string{fiber.MethodGet, fiber.MethodPost}, ","),
  AllowHeaders: "Content-Type",
  ExposeHeaders: "Content-Length",
}))

// After
app.Use(cors.New(cors.Config{
  AllowOrigins: []string{"https://example.com", "https://example2.com"},
  AllowMethods: []string{fiber.MethodGet, fiber.MethodPost},
  AllowHeaders: []string{"Content-Type"},
  ExposeHeaders: []string{"Content-Length"},
}))
```
...