Rewrite

The Rewrite middleware remaps the request path using custom rules, helping with backward compatibility and cleaner URLs. Rules are tried in the order you write them and the first match wins.

Signatures

func New(config ...Config) fiber.Handler

Config

Property	Type	Description	Default
Next	func(fiber.Ctx) bool	Skip when function returns true.	nil
RuleList	[]Rule	Rules tried in order, first match wins; $1, $2 insert wildcard captures.	nil
Rules	map[string]string	Deprecated. Use RuleList. A map has no order, so precedence is decided by a heuristic.	nil

Set one of RuleList or Rules. With neither, the middleware rewrites nothing.

A rule's From is path text: * matches a run of any bytes but a newline, and every other byte stands for itself, so /preis-1.000-euro rewrites that path and not /preis-1X000-euro. There is no escape for a literal *.

Setting both RuleList and Rules panics.

Rule order

Rules are tried in the order you write them and the first one whose From matches answers, exactly as routes are matched. Nothing reorders a RuleList. Put the specific rules before the catch-alls:

RuleList: []rewrite.Rule{
    {From: "/api/users", To: "/v2/users"},  // checked first
    {From: "/api/*", To: "/v2/$1"},         // takes everything else
}

Written the other way round, /api/* answers /api/users too and the second rule never fires.

note

The deprecated Rules map has no order of its own, so Fiber sorts it: most path text before the first * wins, then most path text overall, then fewest asterisks, then the key itself. That is a rough reading of "most specific", not an exact one, so a long wildcard rule can still outrank a shorter exact one. RuleList is the exact control.

Examples

package main

import (
    "github.com/gofiber/fiber/v3"
    "github.com/gofiber/fiber/v3/middleware/rewrite"
)

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

    app.Use(rewrite.New(rewrite.Config{
      RuleList: []rewrite.Rule{
        {From: "/old", To: "/new"},
        {From: "/old/*", To: "/new/$1"},
      },
    }))

    app.Get("/new", func(c fiber.Ctx) error {
      return c.SendString("Hello, World!")
    })
    app.Get("/new/*", func(c fiber.Ctx) error {
      return c.SendString("Wildcard: " + c.Params("*"))
    })

    app.Listen(":3000")
}

Test

curl http://localhost:3000/old
curl http://localhost:3000/old/hello