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Version: Next

Compress

Compression middleware for Fiber that automatically compresses responses with gzip, deflate, brotli, or zstd based on the client's Accept-Encoding header.

note

Bodies smaller than 200 bytes remain uncompressed because compression would likely increase their size and waste CPU cycles. See the fasthttp source.

Behavior

  • Skips compression for responses that already define Content-Encoding, for range requests, 206 responses, status codes without bodies, or when either side sends Cache-Control: no-transform.
  • HEAD requests negotiate compression so Content-Encoding, Content-Length, ETag, and Vary reflect the encoded representation, but the body is removed before sending.
  • When compression runs, strong ETag values are recomputed from the compressed bytes; when skipped, Accept-Encoding is still merged into Vary unless the header is * or already present.

Signatures

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

Examples

Import the middleware package:

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

Once your Fiber app is initialized, use the middleware like this:

// Initialize default config
app.Use(compress.New())

// Or extend your config for customization
app.Use(compress.New(compress.Config{
Level: compress.LevelBestSpeed, // 1
}))

// Skip middleware for specific routes
app.Use(compress.New(compress.Config{
Next: func(c fiber.Ctx) bool {
return c.Path() == "/dont_compress"
},
Level: compress.LevelBestSpeed, // 1
}))

Config

PropertyTypeDescriptionDefault
Nextfunc(fiber.Ctx) boolSkips this middleware when the function returns true.nil
LevelLevelCompression level to use.LevelDefault (0)

Possible values for the "Level" field are:

  • LevelDisabled (-1): Compression is disabled.
  • LevelDefault (0): Default compression level.
  • LevelBestSpeed (1): Best compression speed.
  • LevelBestCompression (2): Best compression.

Default Config

var ConfigDefault = Config{
Next: nil,
Level: LevelDefault,
}

Constants

// Compression levels
const (
LevelDisabled = -1
LevelDefault = 0
LevelBestSpeed = 1
LevelBestCompression = 2
)