Claude Md Example For Go Fiber API (2026)

Last updated: April 17, 2026

Building a Go Fiber API project becomes significantly more productive when you integrate Claude Code into your workflow. This guide provides concrete examples of how to use Claude’s capabilities to accelerate development, testing, and documentation for your Fiber applications. Whether you are starting a greenfield project or maintaining an existing codebase, the patterns here apply directly to real work.

Setting Up Your Go Fiber Project

Before diving into Claude integration, ensure you have a basic Go Fiber project structure. Initialize your project and install Fiber:

mkdir my-fiber-api && cd my-fiber-api
go mod init my-fiber-api
go get github.com/gofiber/fiber/v2
go get github.com/gofiber/fiber/v2/middleware/logger
go get github.com/gofiber/fiber/v2/middleware/recover
go get github.com/gofiber/fiber/v2/middleware/cors

Create a main.go file that establishes your baseline with common middleware:

package main
import (
 "log"
 "os"
 "github.com/gofiber/fiber/v2"
 "github.com/gofiber/fiber/v2/middleware/cors"
 "github.com/gofiber/fiber/v2/middleware/logger"
 "github.com/gofiber/fiber/v2/middleware/recover"
)
func main() {
 app := fiber.New(fiber.Config{
 ErrorHandler: globalErrorHandler,
 })
 app.Use(logger.New())
 app.Use(recover.New())
 app.Use(cors.New(cors.Config{
 AllowOrigins: os.Getenv("ALLOWED_ORIGINS"),
 AllowHeaders: "Origin, Content-Type, Accept, Authorization",
 }))
 app.Get("/api/health", func(c *fiber.Ctx) error {
 return c.JSON(fiber.Map{"status": "ok", "version": "1.0.0"})
 })
 port := os.Getenv("PORT")
 if port == "" {
 port = "3000"
 }
 log.Fatal(app.Listen(":" + port))
}

This structure gives Claude a clear picture of how your app is wired before you start asking it to add features. Context matters. the more you share upfront, the more accurate the generated code will be.

Using Claude for Route Development

When you need to add new endpoints to your Fiber API, describe your requirements to Claude in plain terms. Instead of asking for generic CRUD, be specific about your business rules. For example:

“Add a /api/users route group with GET (list with pagination), POST (create with email uniqueness check), GET /:id (fetch by ID), PUT /:id (partial update), DELETE /:id (soft delete). Use a User struct with fields: ID uint, Email string, Name string, CreatedAt time.Time, DeletedAt gorm.DeletedAt.”

Claude will scaffold the complete handler file, validation logic, and route registration. Here is the kind of output you can expect and refine:

// handlers/users.go
package handlers
import (
 "github.com/gofiber/fiber/v2"
 "my-fiber-api/models"
 "my-fiber-api/services"
)
type UserHandler struct {
 svc services.UserService
}
func NewUserHandler(svc services.UserService) *UserHandler {
 return &UserHandler{svc: svc}
}
func (h *UserHandler) List(c *fiber.Ctx) error {
 page := c.QueryInt("page", 1)
 limit := c.QueryInt("limit", 20)
 users, total, err := h.svc.List(c.Context(), page, limit)
 if err != nil {
 return err
 }
 return c.JSON(fiber.Map{
 "data": users,
 "total": total,
 "page": page,
 "limit": limit,
 })
}
func (h *UserHandler) Create(c *fiber.Ctx) error {
 var input models.CreateUserInput
 if err := c.BodyParser(&input); err != nil {
 return fiber.NewError(fiber.StatusBadRequest, "invalid request body")
 }
 if err := input.Validate(); err != nil {
 return fiber.NewError(fiber.StatusUnprocessableEntity, err.Error())
 }
 user, err := h.svc.Create(c.Context(), input)
 if err != nil {
 return err
 }
 return c.Status(fiber.StatusCreated).JSON(user)
}

This handler-plus-service pattern is idiomatic Go. Claude generates consistent code when you provide a pattern once and then reference it. “follow the same handler pattern as users” gets you clean results.

Project Layout That Scales

Flat main.go files work for demos but not for production APIs. Ask Claude to help you organize a proper layout:

my-fiber-api/
 main.go
 config/
 config.go # env-based configuration
 handlers/
 users.go
 products.go
 middleware/
 auth.go
 ratelimit.go
 models/
 user.go
 product.go
 services/
 user_service.go
 product_service.go
 repository/
 user_repo.go
 interfaces.go
 routes/
 routes.go # central route registration

Keeping routes in one place makes it easy to audit what is exposed. Claude can generate the entire routes.go from your handler interfaces if you describe which handlers exist.

Testing Your Fiber API with Claude

Testing is where Claude Code produces the most use. Fiber includes a built-in test helper that lets you run requests against the app without starting an HTTP server. Use the tdd skill to drive your development. Describe the expected behavior of your endpoints:

“Write tests for GET /api/users that cover: empty list returns 200 with empty array, pagination params are respected, invalid limit returns 400.”

Claude generates tests like these:

// handlers/users_test.go
package handlers_test
import (
 "encoding/json"
 "net/http"
 "net/http/httptest"
 "testing"
 "github.com/gofiber/fiber/v2"
 "github.com/stretchr/testify/assert"
 "github.com/stretchr/testify/mock"
)
func setupTestApp(handler *UserHandler) *fiber.App {
 app := fiber.New()
 app.Get("/api/users", handler.List)
 app.Post("/api/users", handler.Create)
 app.Get("/api/users/:id", handler.Get)
 app.Put("/api/users/:id", handler.Update)
 app.Delete("/api/users/:id", handler.Delete)
 return app
}
func TestListUsers_EmptyResult(t *testing.T) {
 mockSvc := new(MockUserService)
 mockSvc.On("List", mock.Anything, 1, 20).Return([]models.User{}, int64(0), nil)
 app := setupTestApp(NewUserHandler(mockSvc))
 req := httptest.NewRequest(http.MethodGet, "/api/users", nil)
 resp, err := app.Test(req)
 assert.NoError(t, err)
 assert.Equal(t, 200, resp.StatusCode)
 var body map[string]interface{}
 json.NewDecoder(resp.Body).Decode(&body)
 assert.Equal(t, float64(0), body["total"])
 mockSvc.AssertExpectations(t)
}
func TestListUsers_InvalidLimit(t *testing.T) {
 mockSvc := new(MockUserService)
 app := setupTestApp(NewUserHandler(mockSvc))
 req := httptest.NewRequest(http.MethodGet, "/api/users?limit=abc", nil)
 resp, _ := app.Test(req)
 assert.Equal(t, 400, resp.StatusCode)
}

Notice the mock service pattern. Claude generates both the mock and the test when you provide the service interface. This keeps tests fast and isolated from the database.

Generating API Documentation

Documentation often gets neglected but remains critical for API usability. The pdf skill allows you to generate professional PDF documentation directly from your route definitions. Describe your endpoints to Claude, and it can produce formatted documentation covering request/response schemas, authentication requirements, and example payloads.

For OpenAPI spec generation, describe your handlers and Claude produces a YAML spec you can drop into Swagger UI or Redoc:

Generated OpenAPI fragment for /api/users
paths:
 /api/users:
 get:
 summary: List users
 parameters:
 - name: page
 in: query
 schema:
 type: integer
 default: 1
 - name: limit
 in: query
 schema:
 type: integer
 default: 20
 maximum: 100
 responses:
 "200":
 description: Paginated user list
 content:
 application/json:
 schema:
 $ref: "#/components/schemas/UserListResponse"
 "400":
 description: Invalid query parameters

For markdown-based documentation that integrates with static site generators, describe your API structure and Claude will generate clean, readable documentation files with proper formatting and code examples.

Database Integration Patterns

Go Fiber works well with GORM, sqlx, and pgx directly. When integrating with GORM, give Claude your schema requirements and it generates models with correct tags and associations:

// models/user.go
package models
import (
 "time"
 "gorm.io/gorm"
)
type User struct {
 gorm.Model
 Email string `gorm:"uniqueIndex;not null" json:"email"`
 Name string `gorm:"not null" json:"name"`
 Role string `gorm:"default:user" json:"role"`
 LastLogin *time.Time `json:"last_login,omitempty"`
}
type CreateUserInput struct {
 Email string `json:"email" validate:"required,email"`
 Name string `json:"name" validate:"required,min=2,max=100"`
}
func (i *CreateUserInput) Validate() error {
 // Claude generates validation logic here
 return nil
}

For the repository layer, describe what queries you need and Claude generates methods with proper error wrapping:

// repository/user_repo.go
type UserRepository interface {
 FindAll(ctx context.Context, page, limit int) ([]User, int64, error)
 FindByID(ctx context.Context, id uint) (*User, error)
 FindByEmail(ctx context.Context, email string) (*User, error)
 Create(ctx context.Context, user *User) error
 Update(ctx context.Context, id uint, updates map[string]interface{}) error
 SoftDelete(ctx context.Context, id uint) error
}

Claude can generate the concrete GORM implementation from this interface definition, including the correct Offset and Limit calculations for pagination and Updates vs Save semantics for partial updates.

Middleware Development

Custom middleware is essential for authentication, logging, and request processing. Claude can help you build Fiber middleware with proper signatures. Here is a JWT auth middleware with role-based access:

// middleware/auth.go
package middleware
import (
 "strings"
 "github.com/gofiber/fiber/v2"
 "github.com/golang-jwt/jwt/v5"
)
type Claims struct {
 UserID uint `json:"user_id"`
 Role string `json:"role"`
 jwt.RegisteredClaims
}
func AuthRequired(secret string) fiber.Handler {
 return func(c *fiber.Ctx) error {
 header := c.Get("Authorization")
 if !strings.HasPrefix(header, "Bearer ") {
 return fiber.NewError(fiber.StatusUnauthorized, "missing authorization token")
 }
 tokenStr := strings.TrimPrefix(header, "Bearer ")
 claims := &Claims{}
 token, err := jwt.ParseWithClaims(tokenStr, claims, func(t *jwt.Token) (interface{}, error) {
 return []byte(secret), nil
 })
 if err != nil || !token.Valid {
 return fiber.NewError(fiber.StatusUnauthorized, "invalid or expired token")
 }
 c.Locals("user_id", claims.UserID)
 c.Locals("role", claims.Role)
 return c.Next()
 }
}
func RequireRole(role string) fiber.Handler {
 return func(c *fiber.Ctx) error {
 userRole, ok := c.Locals("role").(string)
 if !ok || userRole != role {
 return fiber.NewError(fiber.StatusForbidden, "insufficient permissions")
 }
 return c.Next()
 }
}

The super-memory skill proves valuable when tracking your middleware chain and understanding which components process each request. Apply middleware in your route registration to keep authorization rules visible in one file:

// routes/routes.go
api := app.Group("/api")
api.Get("/health", handlers.Health)
users := api.Group("/users", middleware.AuthRequired(cfg.JWTSecret))
users.Get("/", userHandler.List)
users.Post("/", middleware.RequireRole("admin"), userHandler.Create)
users.Get("/:id", userHandler.Get)
users.Put("/:id", userHandler.Update)
users.Delete("/:id", middleware.RequireRole("admin"), userHandler.Delete)

Error Handling Strategies

Solid error handling distinguishes production-ready APIs from prototypes. Claude can help implement centralized error handling using Fiber’s ErrorHandler:

// config/errors.go
package config
import (
 "errors"
 "github.com/gofiber/fiber/v2"
)
type APIError struct {
 Code int `json:"-"`
 Message string `json:"error"`
 Details any `json:"details,omitempty"`
}
func (e *APIError) Error() string { return e.Message }
func GlobalErrorHandler(c *fiber.Ctx, err error) error {
 code := fiber.StatusInternalServerError
 message := "internal server error"
 var details any
 var apiErr *APIError
 var fiberErr *fiber.Error
 switch {
 case errors.As(err, &apiErr):
 code = apiErr.Code
 message = apiErr.Message
 details = apiErr.Details
 case errors.As(err, &fiberErr):
 code = fiberErr.Code
 message = fiberErr.Message
 }
 return c.Status(code).JSON(fiber.Map{
 "error": message,
 "details": details,
 })
}

This pattern ensures consistent error responses across all endpoints while maintaining proper HTTP status codes. Callers get a predictable shape regardless of which handler or service layer produced the error.

Performance Comparison: Fiber vs Other Go Frameworks

When choosing Fiber for a project, the performance case is straightforward:

Framework	Requests/sec (echo)	Latency (p99)	Memory/req
Fiber v2	~170,000	~1.2ms	Low
Echo	~130,000	~1.8ms	Low
Gin	~120,000	~2.0ms	Low
net/http	~100,000	~2.5ms	Lowest

Fiber’s speed comes from fasthttp rather than net/http. This matters for high-throughput internal services. For most CRUD APIs, the difference is not the bottleneck. but Fiber’s middleware API and routing syntax are clean enough that it wins on developer experience regardless of the benchmark numbers.

Deployment Considerations

When preparing for production, Claude helps you configure environment-based setup, graceful shutdown, and structured logging output:

// Graceful shutdown pattern
func startServer(app *fiber.App, port string) {
 c := make(chan os.Signal, 1)
 signal.Notify(c, os.Interrupt, syscall.SIGTERM)
 go func() {
 <-c
 log.Println("shutting down server...")
 if err := app.Shutdown(); err != nil {
 log.Printf("error shutting down: %v", err)
 }
 }()
 if err := app.Listen(":" + port); err != nil {
 log.Panic(err)
 }
}

Describe your deployment target. Kubernetes, Docker, or traditional servers. and Claude generates appropriate configuration files. For Docker, it produces a multi-stage Dockerfile that compiles to a minimal final image:

FROM golang:1.22-alpine AS builder
WORKDIR /app
COPY go.mod go.sum ./
RUN go mod download
COPY . .
RUN CGO_ENABLED=0 GOOS=linux go build -o server ./main.go
FROM alpine:3.19
RUN apk --no-cache add ca-certificates
WORKDIR /app
COPY --from=builder /app/server .
EXPOSE 3000
CMD ["./server"]

Conclusion

Integrating Claude Code into your Go Fiber workflow accelerates development across the entire project lifecycle. From initial scaffolding through testing, documentation, and deployment, Claude’s capabilities complement Fiber’s performance with genuine developer productivity. The key is being specific: the more context you share about your data model, your middleware chain, and your business rules, the more directly usable the generated code becomes. Start with interfaces and structs, let Claude fill in the implementations, then refine. This combination enables you to build production-ready APIs faster while maintaining code quality through intelligent assistance and established patterns.

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