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🖥️ REST

The Fiber Client is a high-performance HTTP client built on FastHTTP. It handles both internal service calls and external requests with minimal overhead.

Use the index to jump straight to any client method; filter by name or by category:

Features​

  • Lightweight and fast: built on FastHTTP for minimal overhead.
  • Flexible configuration: set global defaults like timeouts or headers and override them per request.
  • Connection pooling: reuses persistent connections instead of opening new ones.
  • Timeouts and retries: supports per-request deadlines and retry policies for transient errors.

Usage​

Create a client with any required configuration, then send requests:

package main

import (
    "fmt"
    "time"

    "github.com/gofiber/fiber/v3/client"
)

func main() {
    cc := client.New()
    cc.SetTimeout(10 * time.Second)

    // Send a GET request
    resp, err := cc.Get("https://httpbin.org/get")
    if err != nil {
        panic(err)
    }

    fmt.Printf("Status: %d\n", resp.StatusCode())
    fmt.Printf("Body: %s\n", string(resp.Body()))
}

See examples for more detailed usage.

type Client struct {
    logger    log.CommonLogger
    transport httpClientTransport

    header  *Header
    params  *QueryParam
    cookies *Cookie
    path    *PathParam

    jsonMarshal   utils.JSONMarshal
    jsonUnmarshal utils.JSONUnmarshal
    xmlMarshal    utils.XMLMarshal
    xmlUnmarshal  utils.XMLUnmarshal
    cborMarshal   utils.CBORMarshal
    cborUnmarshal utils.CBORUnmarshal

    cookieJar            *CookieJar
    retryConfig          *RetryConfig
    baseURL              string
    userAgent            string
    referer              string
    userRequestHooks     []RequestHook
    builtinRequestHooks  []RequestHook
    userResponseHooks    []ResponseHook
    builtinResponseHooks []ResponseHook

    timeout                   time.Duration
    mu                        sync.RWMutex
    isDebug                   bool
    isPathNormalizingDisabled bool
}

New​

New creates and returns a new Client object.

Signature
func New() *Client

NewWithClient​

NewWithClient creates and returns a new Client object from an existing fasthttp.Client.

Signature
func NewWithClient(c *fasthttp.Client) *Client

REST Methods​

These helpers mirror axios-style method names and send HTTP requests using the configured client:

Get​

Sends a GET request.

Signature
func (c *Client) Get(url string, cfg ...Config) (*Response, error)

Post​

Sends a POST request.

Signature
func (c *Client) Post(url string, cfg ...Config) (*Response, error)

Put​

Sends a PUT request.

Signature
func (c *Client) Put(url string, cfg ...Config) (*Response, error)

Patch​

Sends a PATCH request.

Signature
func (c *Client) Patch(url string, cfg ...Config) (*Response, error)

Query​

Sends a QUERY request.

Signature
func (c *Client) Query(url string, cfg ...Config) (*Response, error)

Delete​

Sends a DELETE request.

Signature
func (c *Client) Delete(url string, cfg ...Config) (*Response, error)

Sends a HEAD request.

Signature
func (c *Client) Head(url string, cfg ...Config) (*Response, error)

Options​

Sends an OPTIONS request.

Signature
func (c *Client) Options(url string, cfg ...Config) (*Response, error)

Custom​

Sends a request with any HTTP method.

Signature
func (c *Client) Custom(url, method string, cfg ...Config) (*Response, error)

Request Configuration​

The Config type holds per-request parameters. JSON is used to serialize the body by default. If multiple body sources are set, precedence is:

  1. Body
  2. FormData
  3. File
type Config struct {
    Ctx context.Context

    UserAgent string
    Referer   string
    Header    map[string]string
    Param     map[string]string
    Cookie    map[string]string
    PathParam map[string]string

    Timeout      time.Duration
    MaxRedirects int

    Body     any
    FormData map[string]string
    File     []*File
}

R​

R gets a Request object from the pool. Call ReleaseRequest when finished.

Signature
func (c *Client) R() *Request

Hooks​

Hooks allow you to add custom logic before a request is sent or after a response is received.

RequestHook​

RequestHook returns user-defined request hooks.

Signature
func (c *Client) RequestHook() []RequestHook

ResponseHook​

ResponseHook returns user-defined response hooks.

Signature
func (c *Client) ResponseHook() []ResponseHook

AddRequestHook​

Adds one or more user-defined request hooks.

Signature
func (c *Client) AddRequestHook(h ...RequestHook) *Client

AddResponseHook​

Adds one or more user-defined response hooks.

Signature
func (c *Client) AddResponseHook(h ...ResponseHook) *Client

JSON​

JSONMarshal​

Returns the JSON marshaler function used by the client.

Signature
func (c *Client) JSONMarshal() utils.JSONMarshal

JSONUnmarshal​

Returns the JSON unmarshaler function used by the client.

Signature
func (c *Client) JSONUnmarshal() utils.JSONUnmarshal

SetJSONMarshal​

Sets a custom JSON marshaler.

Signature
func (c *Client) SetJSONMarshal(f utils.JSONMarshal) *Client

SetJSONUnmarshal​

Sets a custom JSON unmarshaler.

Signature
func (c *Client) SetJSONUnmarshal(f utils.JSONUnmarshal) *Client

XML​

XMLMarshal​

Returns the XML marshaler function used by the client.

Signature
func (c *Client) XMLMarshal() utils.XMLMarshal

XMLUnmarshal​

Returns the XML unmarshaler function used by the client.

Signature
func (c *Client) XMLUnmarshal() utils.XMLUnmarshal

SetXMLMarshal​

Sets a custom XML marshaler.

Signature
func (c *Client) SetXMLMarshal(f utils.XMLMarshal) *Client

SetXMLUnmarshal​

Sets a custom XML unmarshaler.

Signature
func (c *Client) SetXMLUnmarshal(f utils.XMLUnmarshal) *Client

CBOR​

CBORMarshal​

Returns the CBOR marshaler function used by the client.

Signature
func (c *Client) CBORMarshal() utils.CBORMarshal

CBORUnmarshal​

Returns the CBOR unmarshaler function used by the client.

Signature
func (c *Client) CBORUnmarshal() utils.CBORUnmarshal

SetCBORMarshal​

Sets a custom CBOR marshaler.

Signature
func (c *Client) SetCBORMarshal(f utils.CBORMarshal) *Client

SetCBORUnmarshal​

Sets a custom CBOR unmarshaler.

Signature
func (c *Client) SetCBORUnmarshal(f utils.CBORUnmarshal) *Client

TLS​

TLSConfig​

Returns the client's TLS configuration. If none is set, it initializes a new configuration with MinVersion defaulting to TLS 1.2.

Signature
func (c *Client) TLSConfig() *tls.Config

SetTLSConfig​

Sets the TLS configuration for the client.

Signature
func (c *Client) SetTLSConfig(config *tls.Config) *Client

SetCertificates​

Adds client certificates to the TLS configuration.

Signature
func (c *Client) SetCertificates(certs ...tls.Certificate) *Client

SetRootCertificate​

Adds one or more root certificates to the client's trust store.

Signature
func (c *Client) SetRootCertificate(path string) *Client

SetRootCertificateFromString​

Adds one or more root certificates from a string.

Signature
func (c *Client) SetRootCertificateFromString(pem string) *Client

SetProxyURL​

Sets a proxy URL for the client. All subsequent requests will use this proxy.

Signature
func (c *Client) SetProxyURL(proxyURL string) error

Response Streaming​

StreamResponseBody​

Returns whether response body streaming is enabled. When enabled, the response body is not fully loaded into memory and can be read as a stream using Response.BodyStream(). This is useful for handling large responses or server-sent events (SSE).

Signature
func (c *Client) StreamResponseBody() bool

SetStreamResponseBody​

Enables or disables response body streaming. When enabled, responses can be consumed incrementally without loading the entire body into memory.

Signature
func (c *Client) SetStreamResponseBody(enable bool) *Client

Example:

Example
cc := client.New()
cc.SetStreamResponseBody(true)

resp, err := cc.Get("https://example.com/large-file")
if err != nil {
    panic(err)
}
defer resp.Close()

// Check if response is streaming
if resp.IsStreaming() {
    // Read body incrementally
    reader := resp.BodyStream()
    buf := make([]byte, 4096)
    for {
        n, err := reader.Read(buf)
        if n > 0 {
            // Process chunk...
        }
        if err == io.EOF {
            break
        }
        if err != nil {
            panic(err)
        }
    }
} else {
    // Regular body access
    body := resp.Body()
    fmt.Println(string(body))
}

Server-Sent Events Example:

SSE Example
cc := client.New()
cc.SetStreamResponseBody(true)

resp, err := cc.Get("https://example.com/events")
if err != nil {
    panic(err)
}
defer resp.Close()

reader := bufio.NewReader(resp.BodyStream())
for {
    line, err := reader.ReadString('\n')
    if err == io.EOF {
        break
    }
    if err != nil {
        panic(err)
    }
    fmt.Print(line) // Process SSE event
}

RetryConfig​

Returns the retry configuration of the client.

Signature
func (c *Client) RetryConfig() *RetryConfig

SetRetryConfig​

Sets the retry configuration for the client.

Signature
func (c *Client) SetRetryConfig(config *RetryConfig) *Client

BaseURL​

BaseURL​

BaseURL returns the base URL currently set in the client.

Signature
func (c *Client) BaseURL() string

SetBaseURL​

Sets a base URL prefix for all requests made by the client.

Signature
func (c *Client) SetBaseURL(url string) *Client

Example:

Example
cc := client.New()
cc.SetBaseURL("https://httpbin.org/")

resp, err := cc.Get("/get")
if err != nil {
    panic(err)
}

fmt.Println(string(resp.Body()))
Click here to see the result
{
  "args": {},
  ...
}

Headers​

Retrieves all values of a header key at the client level. The returned values apply to all requests.

Signature
func (c *Client) Header(key string) []string

AddHeader​

Adds a single header to all requests initiated by this client.

Signature
func (c *Client) AddHeader(key, val string) *Client

SetHeader​

Sets a single header, overriding any existing headers with the same key.

Signature
func (c *Client) SetHeader(key, val string) *Client

AddHeaders​

Adds multiple headers at once, all applying to all future requests from this client.

Signature
func (c *Client) AddHeaders(h map[string][]string) *Client

SetHeaders​

Sets multiple headers at once, overriding previously set headers.

Signature
func (c *Client) SetHeaders(h map[string]string) *Client

Query Parameters​

Param​

Returns the values for a given query parameter key.

Signature
func (c *Client) Param(key string) []string

AddParam​

Adds a single query parameter for all requests.

Signature
func (c *Client) AddParam(key, val string) *Client

SetParam​

Sets a single query parameter, overriding previously set values.

Signature
func (c *Client) SetParam(key, val string) *Client

AddParams​

Adds multiple query parameters from a map of string slices.

Signature
func (c *Client) AddParams(m map[string][]string) *Client

SetParams​

Sets multiple query parameters from a map, overriding previously set values.

Signature
func (c *Client) SetParams(m map[string]string) *Client

SetParamsWithStruct​

Sets multiple query parameters from a struct. Nested structs are not currently supported.

Signature
func (c *Client) SetParamsWithStruct(v any) *Client

DelParams​

Deletes one or more query parameters.

Signature
func (c *Client) DelParams(key ...string) *Client

UserAgent & Referer​

SetUserAgent​

Sets the user agent header for all requests.

Signature
func (c *Client) SetUserAgent(ua string) *Client

SetReferer​

Sets the referer header for all requests.

Signature
func (c *Client) SetReferer(r string) *Client

Path Parameters​

PathParam​

Returns the value of a named path parameter, if set.

Signature
func (c *Client) PathParam(key string) string

SetPathParam​

Sets a single path parameter.

Signature
func (c *Client) SetPathParam(key, val string) *Client

SetPathParams​

Sets multiple path parameters at once.

Signature
func (c *Client) SetPathParams(m map[string]string) *Client

SetPathParamsWithStruct​

Sets multiple path parameters from a struct.

Signature
func (c *Client) SetPathParamsWithStruct(v any) *Client

DelPathParams​

Deletes one or more path parameters.

Signature
func (c *Client) DelPathParams(key ...string) *Client

Cookies​

Returns the value of a named cookie if set at the client level.

Signature
func (c *Client) Cookie(key string) string

SetCookie​

Sets a single cookie for all requests.

Signature
func (c *Client) SetCookie(key, val string) *Client

Example:

Example
cc := client.New()
cc.SetCookie("john", "doe")

resp, err := cc.Get("https://httpbin.org/cookies")
if err != nil {
    panic(err)
}

fmt.Println(string(resp.Body()))
Click here to see the result
{
  "cookies": {
    "john": "doe"
  }
}

SetCookies​

Sets multiple cookies at once.

Signature
func (c *Client) SetCookies(m map[string]string) *Client

SetCookiesWithStruct​

Sets multiple cookies from a struct.

Signature
func (c *Client) SetCookiesWithStruct(v any) *Client

DelCookies​

Deletes one or more cookies.

Signature
func (c *Client) DelCookies(key ...string) *Client

Timeout​

SetTimeout​

Sets a default timeout for all requests, which can be overridden per request.

Signature
func (c *Client) SetTimeout(t time.Duration) *Client

Debugging​

Debug​

Enables debug-level logging output.

Signature
func (c *Client) Debug() *Client

DisableDebug​

Disables debug-level logging output.

Signature
func (c *Client) DisableDebug() *Client

SetCookieJar​

Assigns a cookie jar to the client to store and manage cookies across requests.

Signature
func (c *Client) SetCookieJar(cookieJar *CookieJar) *Client

Dial & Logger​

SetDial​

Sets a custom dial function.

Signature
func (c *Client) SetDial(dial fasthttp.DialFunc) *Client

SetLogger​

Sets the logger instance used by the client.

Signature
func (c *Client) SetLogger(logger log.CommonLogger) *Client

Logger​

Returns the current logger instance.

Signature
func (c *Client) Logger() log.CommonLogger

Reset​

Reset​

Clears and resets the client to its default state and reinstates the default fasthttp.Client transport.

Signature
func (c *Client) Reset()

Default Client​

Fiber provides a default client (created with New()). You can configure it or replace it as needed.

C​

C returns the default client.

Signature
func C() *Client

Get​

Get is a convenience method that sends a GET request using the defaultClient.

Signature
func Get(url string, cfg ...Config) (*Response, error)

Post​

Post is a convenience method that sends a POST request using the defaultClient.

Signature
func Post(url string, cfg ...Config) (*Response, error)

Put​

Put is a convenience method that sends a PUT request using the defaultClient.

Signature
func Put(url string, cfg ...Config) (*Response, error)

Patch​

Patch is a convenience method that sends a PATCH request using the defaultClient.

Signature
func Patch(url string, cfg ...Config) (*Response, error)

Query​

Query is a convenience method that sends a QUERY request using the defaultClient.

Signature
func Query(url string, cfg ...Config) (*Response, error)

Delete​

Delete is a convenience method that sends a DELETE request using the defaultClient.

Signature
func Delete(url string, cfg ...Config) (*Response, error)

Head​

Head sends a HEAD request using the defaultClient, a convenience method.

Signature
func Head(url string, cfg ...Config) (*Response, error)

Options​

Options is a convenience method that sends an OPTIONS request using the defaultClient.

Signature
func Options(url string, cfg ...Config) (*Response, error)

Replace​

Replace replaces the default client with a new one. It returns a function that can restore the old client.

caution

Replacing the default client is concurrency-safe, but mutating the same Client instance still requires external synchronization.

Signature
func Replace(c *Client) func()