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Documentation Index

Fetch the complete documentation index at: https://mintlify.com/gofiber/fiber/llms.txt

Use this file to discover all available pages before exploring further.

Common questions about using Fiber, its design decisions, and best practices. If you have a question not covered here, feel free to open an issue or ask in our Discord community.

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Getting Started

There’s no single answer; the ideal structure depends on your application’s scale and team. Fiber makes no assumptions about project layout.Routes and other application logic can live in any files or directories. For inspiration, see:
Air automatically restarts your Go application when source files change, speeding development.To use Air in a Fiber project:
  1. Install Air by downloading the appropriate binary for your operating system from the GitHub release page or by building the tool from source.
  2. Create a configuration file for Air in your project directory, such as .air.toml or air.conf: 
# .air.toml
root = "."
tmp_dir = "tmp"
[build]
  cmd = "go build -o ./tmp/main ."
  bin = "./tmp/main"
  delay = 1000 # ms
  exclude_dir = ["assets", "tmp", "vendor"]
  include_ext = ["go", "tpl", "tmpl", "html"]
  exclude_regex = ["_test\\.go"]
  1. Start your Fiber application with Air:
air
As you edit source files, Air detects the changes and restarts the application.A complete example is available in the Fiber Recipes repository.

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Error Handling

To override the default error handler, provide a custom one in the Config when creating a new Fiber instance.
app := fiber.New(fiber.Config{
    ErrorHandler: func(c fiber.Ctx, err error) error {
        return c.Status(fiber.StatusInternalServerError).SendString(err.Error())
    },
})
We have a dedicated page explaining how error handling works in Fiber, see Error Handling.
If you’re using v2.32.0 or later, implement a custom error handler as shown above or read more at Error Handling.If you’re using v2.31.0 or earlier, the error handler will not capture 404 errors. Instead, add a middleware function at the very bottom of the stack (below all other functions) to handle a 404 response:
app.Use(func(c fiber.Ctx) error {
    return c.Status(fiber.StatusNotFound).SendString("Sorry can't find that!")
})

​
Templates and Rendering

Fiber currently supports 9 template engines in our gofiber/template middleware:To learn more about using Templates in Fiber, see Templates.

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Routing and Networking

Yes, Fiber supports subdomain routing. Here’s an example:
package main

import (
    "log"

    "github.com/gofiber/fiber/v3"
    "github.com/gofiber/fiber/v3/middleware/logger"
)

type Host struct {
    Fiber *fiber.App
}

func main() {
    hosts := map[string]*Host{}
    
    //-----
    // API
    //-----
    api := fiber.New()
    api.Use(logger.New(logger.Config{
        Format: "[${ip}]:${port} ${status} - ${method} ${path}\n",
    }))
    hosts["api.localhost:3000"] = &Host{api}
    api.Get("/", func(c fiber.Ctx) error {
        return c.SendString("API")
    })
    
    //------
    // Blog
    //------
    blog := fiber.New()
    blog.Use(logger.New(logger.Config{
        Format: "[${ip}]:${port} ${status} - ${method} ${path}\n",
    }))
    hosts["blog.localhost:3000"] = &Host{blog}
    blog.Get("/", func(c fiber.Ctx) error {
        return c.SendString("Blog")
    })
    
    //---------
    // Website
    //---------
    site := fiber.New()
    site.Use(logger.New(logger.Config{
        Format: "[${ip}]:${port} ${status} - ${method} ${path}\n",
    }))
    hosts["localhost:3000"] = &Host{site}
    site.Get("/", func(c fiber.Ctx) error {
        return c.SendString("Website")
    })
    
    // Server
    app := fiber.New()
    app.Use(func(c fiber.Ctx) error {
        host := hosts[c.Hostname()]
        if host == nil {
            return c.SendStatus(fiber.StatusNotFound)
        }
        host.Fiber.Handler()(c.Context())
        return nil
    })
    
    log.Fatal(app.Listen(":3000"))
}
For more information, see issue #750.

​
Compatibility and Integration

Fiber can register common net/http handlers directly—just pass an http.Handler, http.HandlerFunc, compatible function, or even a native fasthttp.RequestHandler to your routing method.For other interoperability scenarios, the adaptor middleware provides utilities for converting between Fiber and net/http. It allows seamless integration of net/http handlers, middleware, and requests into Fiber applications, and vice versa.
Performance trade-offs: Converted net/http handlers run through a compatibility layer. They won’t expose fiber.Ctx or Fiber-specific helpers, and the extra adaptation work makes them slower than native Fiber handlers. Use them when interoperability matters, but prefer Fiber handlers for maximum performance.
For details on how to:
  • Convert net/http handlers to Fiber handlers
  • Convert Fiber handlers to net/http handlers
  • Convert fiber.Ctx to http.Request
See the dedicated documentation: Adaptor Documentation.
Yes, but with some considerations:Fiber is built on top of fasthttp rather than net/http for performance reasons. However, Fiber provides:
  • Adaptor middleware for converting between Fiber and net/http handlers
  • Similar API to Express.js and other web frameworks for easier learning
  • Context wrappers that can be converted to http.Request and http.ResponseWriter
While you can integrate net/http handlers, using native Fiber handlers will provide better performance.

​
Performance and Architecture

Fiber achieves exceptional performance through several design decisions:
  1. Built on fasthttp: Uses fasthttp instead of net/http, which is optimized for speed
  2. Zero-allocation router: Custom router designed to minimize memory allocations
  3. Efficient memory pooling: Reuses objects to reduce garbage collection pressure
  4. Optimized middleware: Middleware pipeline is designed for minimal overhead
  5. No reflection in hot paths: Avoids expensive reflection operations in critical code paths
See our Benchmarks for detailed performance comparisons.
Zero-allocation routing means the router doesn’t allocate new memory for most operations, reducing garbage collection overhead and improving performance.Fiber’s router achieves this by:
  • Reusing route parameter buffers
  • Using memory pools for common objects
  • Avoiding unnecessary string allocations
  • Optimizing path matching algorithms
This is particularly beneficial for high-traffic applications where every allocation counts.
Yes, Fiber is production-ready and used by many companies in production environments.Fiber provides:
  • Battle-tested foundation: Built on fasthttp, which is widely used in production
  • Active maintenance: Regular updates and security patches
  • Large community: Extensive middleware ecosystem and community support
  • Proven performance: Excellent benchmarks and real-world performance
However, always:
  • Test thoroughly with your specific use case
  • Monitor performance in production
  • Follow security best practices
  • Keep dependencies updated

​
Community and Support

Yes, we have a Discord server with rooms for every topic.If you have questions or just want to chat, join us via this invite link.Discord Community
We welcome contributions! Here’s how you can help:
  1. Report bugs: Open an issue on GitHub
  2. Submit PRs: Fix bugs or add features
  3. Improve docs: Help improve documentation
  4. Create middleware: Build and share middleware packages
  5. Help others: Answer questions on Discord and GitHub
Check out our Contributing Guide for more details.

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Advanced Topics

Absolutely! Fiber is excellent for microservices due to:
  • Low resource footprint: Uses minimal memory and CPU
  • Fast startup time: Quickly starts and stops for container environments
  • High throughput: Handles many requests efficiently
  • Small binary size: Compiles to compact executables
Common microservice patterns with Fiber:
  • REST APIs
  • gRPC services (with adaptor)
  • Event-driven services
  • Service mesh components
Fiber supports WebSockets through the WebSocket middleware:
import "github.com/gofiber/fiber/v3/middleware/websocket"

app.Use("/ws", func(c fiber.Ctx) error {
    if websocket.IsWebSocketUpgrade(c) {
        return c.Next()
    }
    return fiber.ErrUpgradeRequired
})

app.Get("/ws/:id", websocket.New(func(c *websocket.Conn) {
    // WebSocket logic here
}))
See the WebSocket middleware documentation for more details.
Yes, you can run multiple Fiber applications:
  1. On different ports:
app1 := fiber.New()
app2 := fiber.New()

go app1.Listen(":3000")
app2.Listen(":3001")
  1. Using app mounting:
api := fiber.New()
api.Get("/users", getUsers)

app := fiber.New()
app.Mount("/api", api)
  1. Subdomain routing (see example above)
Have a question not answered here? Visit our Discord community or open an issue on GitHub.

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