Fuego 🔥

The framework for busy Go developers

🚀 Explore and contribute to our 2025 Roadmap! 🚀

Production-ready Go API framework generating OpenAPI documentation from code. Inspired by Nest, built for Go developers.

Also empowers templating with html/template, a-h/templ and maragudk/gomponents: see the example running live.

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][gin-gonic-issue] 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
• Adaptors: Fuego can be plugged to an existing Gin or Echo server to generate OpenAPI documentation

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, "/user/{user}", myController)

	s.Run()
}

func myController(c fuego.ContextWithBody[MyInput]) (*MyOutput, error) {
	body, err := c.Body()
	if err != nil {
		return nil, err
	}

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

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
}

More OpenAPI documentation

package main

import (
	"github.com/go-fuego/fuego"
	"github.com/go-fuego/fuego/option"
	"github.com/go-fuego/fuego/param"
)

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

	// Custom OpenAPI options
	fuego.Post(s, "/", myController,
		option.Description("This route does something..."),
		option.Summary("This is my summary"),
		option.Tags("MyTag"), // A tag is set by default according to the return type (can be deactivated)
		option.Deprecated(),  // Marks the route as deprecated in the OpenAPI spec

		option.Query("name", "Declares a query parameter with default value", param.Default("Carmack")),
		option.Header("Authorization", "Bearer token", param.Required()),
		optionPagination,
		optionCustomBehavior,
	)

	s.Run()
}

var optionPagination = option.Group(
	option.QueryInt("page", "Page number", param.Default(1), param.Example("1st page", 1), param.Example("42nd page", 42)),
	option.QueryInt("perPage", "Number of items per page"),
)

var optionCustomBehavior = func(r *fuego.BaseRoute) {
	r.XXX = "YYY"
}

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.

• Simple CRUD with OpenAPI
• Full app with HTML rendering

package main

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

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

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"}

From net/http to Fuego in 10s

Views

Before

After

Diff

Benefits of using Fuego views (controllers returning HTML)

• Never forget to return after an error
• OpenAPI schema generated, listing all the routes
• Deserialization and validation are easier
• Transition to Fuego is easy and fast

Contributing

See the contributing guide. Thanks to [everyone who