fiber.md

id	title	description	sidebar_position
fiber	📦 Fiber	Fiber represents the fiber package where you start to create an instance.	1

import Reference from '@site/src/components/reference';

Server start

New

This method creates a new App named instance. You can pass optional config when creating a new instance.

func New(config ...Config) *App

// Default config
app := fiber.New()

// ...

Config

You can pass an optional Config when creating a new Fiber instance.

// Custom config
app := fiber.New(fiber.Config{
    CaseSensitive: true,
    StrictRouting: true,
    ServerHeader:  "Fiber",
    AppName: "Test App v1.0.1",
})

// ...

Config fields

Property	Type	Description	Default
AppName	string	This allows to setup app name for the app	""
BodyLimit	int	Sets the maximum allowed size for a request body, if the size exceeds the configured limit, it sends 413 - Request Entity Too Large response.	4 * 1024 * 1024
CaseSensitive	bool	When enabled, /Foo and /foo are different routes. When disabled, /Fooand /foo are treated the same.	false
ColorScheme	Colors	You can define custom color scheme. They'll be used for startup message, route list and some middlewares.	DefaultColors
CompressedFileSuffixes	map[string]string	Adds a suffix to the original file name and tries saving the resulting compressed file under the new file name.	{"gzip": ".fiber.gz", "br": ".fiber.br", "zstd": ".fiber.zst"}
Concurrency	int	Maximum number of concurrent connections.	256 * 1024
DisableDefaultContentType	bool	When set to true, causes the default Content-Type header to be excluded from the Response.	false
DisableDefaultDate	bool	When set to true causes the default date header to be excluded from the response.	false
DisableHeaderNormalizing	bool	By default all header names are normalized: conteNT-tYPE -> Content-Type	false
DisableKeepalive	bool	Disable keep-alive connections, the server will close incoming connections after sending the first response to the client	false
DisablePreParseMultipartForm	bool	Will not pre parse Multipart Form data if set to true. This option is useful for servers that desire to treat multipart form data as a binary blob, or choose when to parse the data.	false
EnableIPValidation	bool	If set to true, c.IP() and c.IPs() will validate IP addresses before returning them. Also, c.IP() will return only the first valid IP rather than just the raw header value that may be a comma separated string. WARNING: There is a small performance cost to doing this validation. Keep disabled if speed is your only concern and your application is behind a trusted proxy that already validates this header.	false
EnableSplittingOnParsers	bool	EnableSplittingOnParsers splits the query/body/header parameters by comma when it's true. For example, you can use it to parse multiple values from a query parameter like this: /api?foo=bar,baz == foo[]=bar&foo[]=baz	false
TrustProxy	bool	When set to true, fiber will check whether proxy is trusted, using TrustProxyConfig.Proxies list. By default c.Protocol() will get value from X-Forwarded-Proto, X-Forwarded-Protocol, X-Forwarded-Ssl or X-Url-Scheme header, c.IP() will get value from ProxyHeader header, c.Hostname() will get value from X-Forwarded-Host header. If TrustProxy is true, and RemoteIP is in the list of TrustProxyConfig.Proxies c.Protocol(), c.IP(), and c.Hostname() will have the same behaviour when TrustProxy disabled, if RemoteIP isn't in the list, c.Protocol() will return https when a TLS connection is handled by the app, or http otherwise, c.IP() will return RemoteIP() from fasthttp context, c.Hostname() will return fasthttp.Request.URI().Host()	false
ErrorHandler	ErrorHandler	ErrorHandler is executed when an error is returned from fiber.Handler. Mounted fiber error handlers are retained by the top-level app and applied on prefix associated requests.	DefaultErrorHandler
GETOnly	bool	Rejects all non-GET requests if set to true. This option is useful as anti-DoS protection for servers accepting only GET requests. The request size is limited by ReadBufferSize if GETOnly is set.	false
IdleTimeout	time.Duration	The maximum amount of time to wait for the next request when keep-alive is enabled. If IdleTimeout is zero, the value of ReadTimeout is used.	nil
Immutable	bool	When enabled, all values returned by context methods are immutable. By default, they are valid until you return from the handler; see issue #185.	false
JSONEncoder	utils.JSONMarshal	Allowing for flexibility in using another json library for encoding.	json.Marshal
JSONDecoder	utils.JSONUnmarshal	Allowing for flexibility in using another json library for decoding.	json.Unmarshal
CBOREncoder	utils.CBORMarshal	Allowing for flexibility in using another cbor library for encoding.	cbor.Marshal
CBORDecoder	utils.CBORUnmarshal	Allowing for flexibility in using another cbor library for decoding.	cbor.Unmarshal
PassLocalsToViews	bool	PassLocalsToViews Enables passing of the locals set on a fiber.Ctx to the template engine. See our Template Middleware for supported engines.	false
ProxyHeader	string	This will enable c.IP() to return the value of the given header key. By default c.IP()will return the Remote IP from the TCP connection, this property can be useful if you are behind a load balancer e.g. X-Forwarded-*.	""
ReadBufferSize	int	per-connection buffer size for requests' reading. This also limits the maximum header size. Increase this buffer if your clients send multi-KB RequestURIs and/or multi-KB headers (for example, BIG cookies).	4096
ReadTimeout	time.Duration	The amount of time allowed to read the full request, including the body. The default timeout is unlimited.	nil
ReduceMemoryUsage	bool	Aggressively reduces memory usage at the cost of higher CPU usage if set to true.	false
RequestMethods	[]string	RequestMethods provides customizability for HTTP methods. You can add/remove methods as you wish.	DefaultMethods
ServerHeader	string	Enables the Server HTTP header with the given value.	""
StreamRequestBody	bool	StreamRequestBody enables request body streaming, and calls the handler sooner when given body is larger than the current limit.	false
StrictRouting	bool	When enabled, the router treats /foo and /foo/ as different. Otherwise, the router treats /foo and /foo/ as the same.	false
StructValidator	StructValidator	If you want to validate header/form/query... automatically when to bind, you can define struct validator. Fiber doesn't have default validator, so it'll skip validator step if you don't use any validator.	nil
TrustProxyConfig	TrustProxyConfig	Configure trusted proxy IP's. Look at TrustProxy doc. TrustProxyConfig.Proxies can take IP or IP range addresses.	nil
UnescapePath	bool	Converts all encoded characters in the route back before setting the path for the context, so that the routing can also work with URL encoded special characters	false
Views	Views	Views is the interface that wraps the Render function. See our Template Middleware for supported engines.	nil
ViewsLayout	string	Views Layout is the global layout for all template render until override on Render function. See our Template Middleware for supported engines.	""
WriteBufferSize	int	Per-connection buffer size for responses' writing.	4096
WriteTimeout	time.Duration	The maximum duration before timing out writes of the response. The default timeout is unlimited.	nil
XMLEncoder	utils.XMLMarshal	Allowing for flexibility in using another XML library for encoding.	xml.Marshal
XMLDecoder	utils.XMLUnmarshal	Allowing for flexibility in using another XML library for decoding.	xml.Unmarshal

Server listening

Config

You can pass an optional ListenConfig when calling the Listen or Listener method.

// Custom config
app.Listen(":8080", fiber.ListenConfig{
    EnablePrefork: true,
    DisableStartupMessage: true,
})

Config fields

Property	Type	Description	Default
BeforeServeFunc	func(app *App) error	Allows customizing and accessing fiber app before serving the app.	nil
CertClientFile	string	Path of the client certificate. If you want to use mTLS, you must enter this field.	""
CertFile	string	Path of the certificate file. If you want to use TLS, you must enter this field.	""
CertKeyFile	string	Path of the certificate's private key. If you want to use TLS, you must enter this field.	""
DisableStartupMessage	bool	When set to true, it will not print out the «Fiber» ASCII art and listening address.	false
EnablePrefork	bool	When set to true, this will spawn multiple Go processes listening on the same port.	false
EnablePrintRoutes	bool	If set to true, will print all routes with their method, path, and handler.	false
GracefulContext	context.Context	Field to shutdown Fiber by given context gracefully.	nil
ShutdownTimeout	time.Duration	Specifies the maximum duration to wait for the server to gracefully shutdown. When the timeout is reached, the graceful shutdown process is interrupted and forcibly terminated, and the context.DeadlineExceeded error is passed to the OnPostShutdown callback. Set to 0 to disable the timeout and wait indefinitely.	10 * time.Second
ListenerAddrFunc	func(addr net.Addr)	Allows accessing and customizing net.Listener.	nil
ListenerNetwork	string	Known networks are "tcp", "tcp4" (IPv4-only), "tcp6" (IPv6-only). WARNING: When prefork is set to true, only "tcp4" and "tcp6" can be chosen.	tcp4
TLSConfigFunc	func(tlsConfig *tls.Config)	Allows customizing tls.Config as you want.	nil
AutoCertManager	*autocert.Manager	Manages TLS certificates automatically using the ACME protocol. Enables integration with Let's Encrypt or other ACME-compatible providers.	nil
TLSMinVersion	uint16	Allows customizing the TLS minimum version.	tls.VersionTLS12

Listen

Listen serves HTTP requests from the given address.

func (app *App) Listen(addr string, config ...ListenConfig) error

// Listen on port :8080 
app.Listen(":8080")

// Listen on port :8080 with Prefork 
app.Listen(":8080", fiber.ListenConfig{EnablePrefork: true})

// Custom host
app.Listen("127.0.0.1:8080")

Prefork

Prefork is a feature that allows you to spawn multiple Go processes listening on the same port. This can be useful for scaling across multiple CPU cores.

app.Listen(":8080", fiber.ListenConfig{EnablePrefork: true})

This distributes the incoming connections between the spawned processes and allows more requests to be handled simultaneously.

TLS

TLS serves HTTPs requests from the given address using certFile and keyFile paths to as TLS certificate and key file.

app.Listen(":443", fiber.ListenConfig{CertFile: "./cert.pem", CertKeyFile: "./cert.key"})

TLS with certificate

app.Listen(":443", fiber.ListenConfig{CertClientFile: "./ca-chain-cert.pem"})

TLS with certFile, keyFile and clientCertFile

app.Listen(":443", fiber.ListenConfig{CertFile: "./cert.pem", CertKeyFile: "./cert.key", CertClientFile: "./ca-chain-cert.pem"})

TLS AutoCert support (ACME / Let's Encrypt)

Provides automatic access to certificates management from Let's Encrypt and any other ACME-based providers.

// Certificate manager
certManager := &autocert.Manager{
    Prompt: autocert.AcceptTOS,
    // Replace with your domain name
    HostPolicy: autocert.HostWhitelist("example.com"),
    // Folder to store the certificates
    Cache: autocert.DirCache("./certs"),
}

app.Listen(":444", fiber.ListenConfig{
    AutoCertManager:    certManager,
})

Listener

You can pass your own net.Listener using the Listener method. This method can be used to enable TLS/HTTPS with a custom tls.Config.

func (app *App) Listener(ln net.Listener, config ...ListenConfig) error

ln, _ := net.Listen("tcp", ":3000")

cer, _:= tls.LoadX509KeyPair("server.crt", "server.key")

ln = tls.NewListener(ln, &tls.Config{Certificates: []tls.Certificate{cer}})

app.Listener(ln)

Server

Server returns the underlying fasthttp server

func (app *App) Server() *fasthttp.Server

func main() {
    app := fiber.New()

    app.Server().MaxConnsPerIP = 1

    // ...
}

Server Shutdown

Shutdown gracefully shuts down the server without interrupting any active connections. Shutdown works by first closing all open listeners and then waits indefinitely for all connections to return to idle before shutting down.

ShutdownWithTimeout will forcefully close any active connections after the timeout expires.

ShutdownWithContext shuts down the server including by force if the context's deadline is exceeded. Shutdown hooks will still be executed, even if an error occurs during the shutdown process, as they are deferred to ensure cleanup happens regardless of errors.

func (app *App) Shutdown() error
func (app *App) ShutdownWithTimeout(timeout time.Duration) error
func (app *App) ShutdownWithContext(ctx context.Context) error

Helper functions

NewError

NewError creates a new HTTPError instance with an optional message.

func NewError(code int, message ...string) *Error

app.Get("/", func(c fiber.Ctx) error {
    return fiber.NewError(782, "Custom error message")
})

IsChild

IsChild determines if the current process is a result of Prefork.

func IsChild() bool

// Config app
app := fiber.New()

app.Get("/", func(c fiber.Ctx) error {
    if !fiber.IsChild() {
        fmt.Println("I'm the parent process")
    } else {
        fmt.Println("I'm a child process")
    }
    return c.SendString("Hello, World!")
})

// ...

// With prefork enabled, the parent process will spawn child processes
app.Listen(":8080", fiber.ListenConfig{EnablePrefork: true})