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JWT

Release Discord Test

JWT returns a JSON Web Token (JWT) auth middleware. For valid token, it sets the token in Ctx.Locals and calls next handler. For invalid token, it returns "401 - Unauthorized" error. For missing token, it returns "400 - Bad Request" error.

Special thanks and credits to Echo

Note: Requires Go 1.25 and above

Install

This middleware supports Fiber v3, install accordingly.

go get -u github.com/gofiber/fiber/v3
go get -u github.com/gofiber/contrib/jwt
go get -u github.com/golang-jwt/jwt/v5

Signature

jwtware.New(config ...jwtware.Config) func(fiber.Ctx) error
jwtware.FromContext(c fiber.Ctx) *jwt.Token

Config

PropertyTypeDescriptionDefault
Nextfunc(fiber.Ctx) boolDefines a function to skip this middleware when it returns truenil
SuccessHandlerfunc(fiber.Ctx) errorExecuted when a token is valid.c.Next()
ErrorHandlerfunc(fiber.Ctx, error) errorErrorHandler defines a function which is executed for an invalid token.401 Invalid or expired JWT
SigningKeySigningKeySigning key used to validate the token. Used as a fallback if SigningKeys is empty.nil
SigningKeysmap[string]SigningKeyMap of signing keys used to validate tokens via the kid header.nil
Claimsjwt.ClaimsClaims are extendable claims data defining token content.jwt.MapClaims{}
ExtractorExtractorFunction used to extract the token from the request.FromAuthHeader("Bearer")
TokenProcessorFuncfunc(token string) (string, error)TokenProcessorFunc processes the token extracted using the Extractor.nil
KeyFuncjwt.KeyfuncUser-defined function that supplies the public key for token validation.nil (uses internal default)
JWKSetURLs[]stringList of JSON Web Key (JWK) Set URLs used to obtain signing keys for parsing JWTs.nil

Available Extractors

JWT middleware uses the shared Fiber extractors (github.com/gofiber/fiber/v3/extractors) and provides several helpers for different token sources. Import them with:

import "github.com/gofiber/fiber/v3/extractors"

For an overview and additional examples, see the Fiber Extractors guide:

  • https://docs.gofiber.io/guide/extractors

  • extractors.FromAuthHeader(prefix string) - Extracts token from the Authorization header using the given scheme prefix (e.g., "Bearer"). This is the recommended and most secure method.

  • extractors.FromHeader(header string) - Extracts token from the specified HTTP header

  • extractors.FromQuery(param string) - Extracts token from URL query parameters

  • extractors.FromParam(param string) - Extracts token from URL path parameters

  • extractors.FromCookie(key string) - Extracts token from cookies

  • extractors.FromForm(param string) - Extracts token from form data

  • extractors.Chain(extrs ...extractors.Extractor) - Tries multiple extractors in order until one succeeds

Security Considerations

⚠️ Security Warning: When choosing an extractor, consider the security implications:

  • URL-based extractors (FromQuery, FromParam): Tokens can leak through server logs, browser referrer headers, proxy logs, and browser history. Use only for development or when security is not a primary concern.
  • Form-based extractors (FromForm): Similar risks to URL extractors, especially if forms are submitted via GET requests.
  • Header-based extractors (FromAuthHeader, FromHeader): Most secure as headers are not typically logged or exposed in referrers.
  • Cookie-based extractors (FromCookie): Secure for web applications but requires proper cookie security settings (HttpOnly, Secure, SameSite).

Recommendation: Use FromAuthHeader("Bearer") (the default) for production applications unless you have specific requirements that necessitate alternative extractors.

HS256 Example

package main

import (
"time"

"github.com/gofiber/fiber/v3"
"github.com/gofiber/fiber/v3/extractors"

jwtware "github.com/gofiber/contrib/jwt"
"github.com/golang-jwt/jwt/v5"
)

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

// Login route
app.Post("/login", login)

// Unauthenticated route
app.Get("/", accessible)

// JWT Middleware
app.Use(jwtware.New(jwtware.Config{
SigningKey: jwtware.SigningKey{Key: []byte("secret")},
Extractor: extractors.FromAuthHeader("Bearer"),
}))

// Restricted Routes
app.Get("/restricted", restricted)

app.Listen(":3000")
}

func login(c fiber.Ctx) error {
user := c.FormValue("user")
pass := c.FormValue("pass")

// Throws Unauthorized error
if user != "john" || pass != "doe" {
return c.SendStatus(fiber.StatusUnauthorized)
}

// Create the Claims
claims := jwt.MapClaims{
"name": "John Doe",
"admin": true,
"exp": time.Now().Add(time.Hour * 72).Unix(),
}

// Create token
token := jwt.NewWithClaims(jwt.SigningMethodHS256, claims)

// Generate encoded token and send it as response.
t, err := token.SignedString([]byte("secret"))
if err != nil {
return c.SendStatus(fiber.StatusInternalServerError)
}

return c.JSON(fiber.Map{"token": t})
}

func accessible(c fiber.Ctx) error {
return c.SendString("Accessible")
}

func restricted(c fiber.Ctx) error {
user := jwtware.FromContext(c)
claims := user.Claims.(jwt.MapClaims)
name := claims["name"].(string)
return c.SendString("Welcome " + name)
}

package main

import (
"github.com/gofiber/fiber/v3"

jwtware "github.com/gofiber/contrib/jwt"
)

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

// JWT Middleware with cookie extractor
app.Use(jwtware.New(jwtware.Config{
SigningKey: jwtware.SigningKey{Key: []byte("secret")},
Extractor: extractors.FromCookie("token"),
}))

app.Get("/protected", func(c fiber.Ctx) error {
return c.SendString("Protected route")
})

app.Listen(":3000")
}

HS256 Test

Login using username and password to retrieve a token.

curl --data "user=john&pass=doe" http://localhost:3000/login

Response

{
"token": "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJleHAiOjE0NjE5NTcxMzZ9.RB3arc4-OyzASAaUhC2W3ReWaXAt_z2Fd3BN4aWTgEY"
}

Request a restricted resource using the token in Authorization request header.

curl localhost:3000/restricted -H "Authorization: Bearer eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJleHAiOjE0NjE5NTcxMzZ9.RB3arc4-OyzASAaUhC2W3ReWaXAt_z2Fd3BN4aWTgEY"

Response

Welcome John Doe

RS256 Example

package main

import (
"crypto/rand"
"crypto/rsa"
"log"
"time"

"github.com/gofiber/fiber/v3"

"github.com/golang-jwt/jwt/v5"

jwtware "github.com/gofiber/contrib/jwt"
)

var (
// Obviously, this is just a test example. Do not do this in production.
// In production, you would have the private key and public key pair generated
// in advance. NEVER add a private key to any GitHub repo.
privateKey *rsa.PrivateKey
)

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

// Just as a demo, generate a new private/public key pair on each run. See note above.
rng := rand.Reader
var err error
privateKey, err = rsa.GenerateKey(rng, 2048)
if err != nil {
log.Fatalf("rsa.GenerateKey: %v", err)
}

// Login route
app.Post("/login", login)

// Unauthenticated route
app.Get("/", accessible)

// JWT Middleware
app.Use(jwtware.New(jwtware.Config{
SigningKey: jwtware.SigningKey{
JWTAlg: jwtware.RS256,
Key: privateKey.Public(),
},
Extractor: extractors.FromAuthHeader("Bearer"),
}))

// Restricted Routes
app.Get("/restricted", restricted)

app.Listen(":3000")
}

func login(c fiber.Ctx) error {
user := c.FormValue("user")
pass := c.FormValue("pass")

// Throws Unauthorized error
if user != "john" || pass != "doe" {
return c.SendStatus(fiber.StatusUnauthorized)
}

// Create the Claims
claims := jwt.MapClaims{
"name": "John Doe",
"admin": true,
"exp": time.Now().Add(time.Hour * 72).Unix(),
}

// Create token
token := jwt.NewWithClaims(jwt.SigningMethodRS256, claims)

// Generate encoded token and send it as response.
t, err := token.SignedString(privateKey)
if err != nil {
log.Printf("token.SignedString: %v", err)
return c.SendStatus(fiber.StatusInternalServerError)
}

return c.JSON(fiber.Map{"token": t})
}

func accessible(c fiber.Ctx) error {
return c.SendString("Accessible")
}

func restricted(c fiber.Ctx) error {
user := jwtware.FromContext(c)
claims := user.Claims.(jwt.MapClaims)
name := claims["name"].(string)
return c.SendString("Welcome " + name)
}

RS256 Test

The RS256 is actually identical to the HS256 test above.

JWK Set Test

The tests are identical to basic JWT tests above, with exception that JWKSetURLs to valid public keys collection in JSON Web Key (JWK) Set format should be supplied. See RFC 7517.

Custom KeyFunc example

KeyFunc defines a user-defined function that supplies the public key for a token validation. The function shall take care of verifying the signing algorithm and selecting the proper key. A user-defined KeyFunc can be useful if tokens are issued by an external party.

When a user-defined KeyFunc is provided, SigningKey, SigningKeys, and SigningMethod are ignored. This is one of the three options to provide a token validation key. The order of precedence is a user-defined KeyFunc, SigningKeys and SigningKey. Required if neither SigningKeys nor SigningKey is provided. Default to an internal implementation verifying the signing algorithm and selecting the proper key.

package main

import (
"fmt"
"github.com/gofiber/fiber/v3"

jwtware "github.com/gofiber/contrib/jwt"
"github.com/golang-jwt/jwt/v5"
)

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

app.Use(jwtware.New(jwtware.Config{
KeyFunc: customKeyFunc(),
Extractor: extractors.FromAuthHeader("Bearer"),
}))

app.Get("/ok", func(c fiber.Ctx) error {
return c.SendString("OK")
})
}

func customKeyFunc() jwt.Keyfunc {
return func(t *jwt.Token) (interface{}, error) {
// Always check the signing method
if t.Method.Alg() != jwtware.HS256 {
return nil, fmt.Errorf("Unexpected jwt signing method=%v", t.Header["alg"])
}

// TODO custom implementation of loading signing key like from a database
signingKey := "secret"

return []byte(signingKey), nil
}
}