Fuego 🔥

The framework for busy Go developers

Build your API or web application in minutes!

Go framework generating OpenAPI documentation from code. Inspired by Nest, built for Go developers.

Also empowers html/template, a-h/templ and maragudk/gomponents: see the example - actually running in prod!

Why Fuego?

Chi, Gin, Fiber and Echo are great frameworks. But since they were designed a long time ago, their current API does not allow them to deduce OpenAPI types from signatures, things that are now possible with generics. Fuego offers a lot of "modern Go based" features that make it easy to develop APIs and web applications.

Features

OpenAPI: Fuego automatically generates OpenAPI documentation
from code - not from comments nor YAML files!
100% net/http compatible (no lock-in): Fuego is built on top of net/http,
so you can use any http.Handler middleware or handler! Fuego also supports
log/slog, context and html/template.
Routing: Fuego router is based on Go 1.22 net/http, with grouping and
middleware support
Serialization/Deserialization: Fuego automatically serializes and
deserializes JSON, XML and HTML Forms based on user-provided structs
(or not, if you want to do it yourself)
Validation: Fuego provides a simple and fast validator based on go-playground/validator
Transformation: easily transform your data by implementing the
fuego.InTransform and fuego.OutTransform interfaces - also useful for
custom validation
Middlewares: easily add a custom net/http middleware
or use the provided middlewares.
Error handling: Fuego provides centralized error handling with
the standard RFC 9457.
Rendering: Fuego provides a simple and fast rendering system based on
html/template - you can still also use your own template system like
templ or gomponents

Examples

Hello World

package main

import "github.com/go-fuego/fuego"

func main() {
	s := fuego.NewServer()

	fuego.Get(s, "/", func(c fuego.ContextNoBody) (string, error) {
		return "Hello, World!", nil
	})

	s.Run()
}

Simple POST

package main

import "github.com/go-fuego/fuego"

type MyInput struct {
	Name string `json:"name" validate:"required"`
}

type MyOutput struct {
	Message string `json:"message"`
}

func main() {
	s := fuego.NewServer()

	// Automatically generates OpenAPI documentation for this route
	fuego.Post(s, "/", func(c *fuego.ContextWithBody[MyInput]) (MyOutput, error) {
		body, err := c.Body()
		if err != nil {
			return MyOutput{}, err
		}

		return MyOutput{
			Message: "Hello, " + body.Name,
		}, nil
	})

	s.Run()
}

With transformation & custom validation

type MyInput struct {
	Name string `json:"name" validate:"required"`
}

// Will be called just before returning c.Body()
func (r *MyInput) InTransform(context.Context) error {
	r.Name = strings.ToLower(r.Name)

	if r.Name == "fuego" {
		return errors.New("fuego is not a valid name for this input")
	}

	return nil
}

Std lib compatibility

package main

import (
	"net/http"

	"github.com/go-fuego/fuego"
)

func main() {
	s := fuego.NewServer()

	// Standard net/http middleware
	fuego.Use(s, func(next http.Handler) http.Handler {
		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
			w.Header().Set("X-Hello", "World")
			next.ServeHTTP(w, r)
		})
	})

	// Standard net/http handler with automatic OpenAPI route declaration
	fuego.GetStd(s, "/std", func(w http.ResponseWriter, r *http.Request) {
		w.Write([]byte("Hello, World!"))
	})

	s.Run()
}

Real-world examples

Please see the /examples folder for more examples.

package main

import (
	"context"
	"errors"
	"net/http"
	"strings"

	chiMiddleware "github.com/go-chi/chi/v5/middleware"
	"github.com/rs/cors"

	"github.com/go-fuego/fuego"
)

type Received struct {
	Name string `json:"name" validate:"required"`
}

type MyResponse struct {
	Message       string `json:"message"`
	BestFramework string `json:"best"`
}

func main() {
	s := fuego.NewServer(
		fuego.WithAddr("localhost:8088"),
	)

	fuego.Use(s, cors.Default().Handler)
	fuego.Use(s, chiMiddleware.Compress(5, "text/html", "text/css"))

	// Fuego 🔥 handler with automatic OpenAPI generation, validation, (de)serialization and error handling
	fuego.Post(s, "/", func(c *fuego.ContextWithBody[Received]) (MyResponse, error) {
		data, err := c.Body()
		if err != nil {
			return MyResponse{}, err
		}

		c.Response().Header().Set("X-Hello", "World")

		return MyResponse{
			Message:       "Hello, " + data.Name,
			BestFramework: "Fuego!",
		}, nil
	})

	// Standard net/http handler with automatic OpenAPI route declaration
	fuego.GetStd(s, "/std", func(w http.ResponseWriter, r *http.Request) {
		w.Write([]byte("Hello, World!"))
	})

	s.Run()
}

// InTransform will be called when using c.Body().
// It can be used to transform the entity and raise custom errors
func (r *Received) InTransform(context.Context) error {
	r.Name = strings.ToLower(r.Name)
	if r.Name == "fuego" {
		return errors.New("fuego is not a name")
	}
	return nil
}

// OutTransform will be called before sending data
func (r *MyResponse) OutTransform(context.Context) error {
	r.Message = strings.ToUpper(r.Message)
	return nil
}

curl  http://localhost:8088/std
# Hello, World!
curl http://localhost:8088 -X POST -d '{"name": "Your Name"}' -H 'Content-Type: application/json'
# {"message":"HELLO, YOUR NAME","best":"Fuego!"}
curl http://localhost:8088 -X POST -d '{"name": "Fuego"}' -H 'Content-Type: application/json'
# {"error":"cannot transform request body: cannot transform request body: fuego is not a name"}