Response Time middleware for Fiber measures how long it takes to process a request and writes the duration to a configurable response header. This is useful for monitoring and debugging performance issues.
Installation
go get -u github.com/gofiber/fiber/v3
go get -u github.com/gofiber/fiber/v3/middleware/responsetime
Signatures
func New(config ...Config) fiber.Handler
Usage
Basic Usage
package main
import (
"github.com/gofiber/fiber/v3"
"github.com/gofiber/fiber/v3/middleware/responsetime"
)
func main() {
app := fiber.New()
// Add response time header to all responses
app.Use(responsetime.New())
app.Get("/", func(c fiber.Ctx) error {
return c.SendString("Hello, World!")
})
app.Listen(":3000")
}
curl -I http://localhost:3000
# Response includes:
# X-Response-Time: 0.523ms
app.Use(responsetime.New(responsetime.Config{
Header: "X-Processing-Time",
}))
Conditional Measurement
// Only measure response time for API routes
app.Use(responsetime.New(responsetime.Config{
Next: func(c fiber.Ctx) bool {
return !strings.HasPrefix(c.Path(), "/api")
},
}))
Configuration
Next
func(fiber.Ctx) bool
default:"nil"
Function to skip this middleware when it returns true.
Header key used to set the response time. Default: X-Response-Time.
Default Configuration
var ConfigDefault = Config{
Next: nil,
Header: fiber.HeaderXResponseTime, // "X-Response-Time"
}
Common Use Cases
app.Use(responsetime.New())
// All responses now include timing information
app.Get("/api/users", func(c fiber.Ctx) error {
// Slow database query
users := db.GetUsers()
return c.JSON(users)
})
// Response header: X-Response-Time: 45.2ms
Custom Logging
app.Use(responsetime.New(responsetime.Config{
Header: "X-Duration",
}))
app.Use(func(c fiber.Ctx) error {
err := c.Next()
// Log the response time
duration := c.Get("X-Duration")
log.Printf("Request to %s took %s", c.Path(), duration)
return err
})
app.Use(responsetime.New())
app.Use(func(c fiber.Ctx) error {
err := c.Next()
// Parse response time and alert if slow
responseTime := c.Get("X-Response-Time")
if strings.Contains(responseTime, "ms") {
// Extract milliseconds and check threshold
// Alert if > 100ms
}
return err
})
How It Works
The middleware:
- Records the start time when the request arrives
- Calls the next handler in the chain
- Calculates the duration after the handler completes
- Formats the duration (e.g., “1.234ms”, “45.6µs”, “1.23s”)
- Sets the configured header with the formatted duration
The time measured includes all middleware and handlers in the chain after this middleware is registered.
Tips
- Place this middleware early in your middleware stack to measure total request time
- Place it later to measure only specific handler execution time
- Use with monitoring tools that parse response headers
- Combine with logger middleware to correlate logs with timing data
- Consider removing or disabling in production if you don’t need the overhead
See Also