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Fix API Rate Limit Exhaustion in Go Fiber

API rate limit exhaustion is a trivial vector for DoS and resource depletion. Without strict throttling, an attacker can saturate your worker pool, exhaust DB connections, or rack up costs on upstream services. In Go Fiber, failing to leverage the built-in limiter middleware means your endpoint is a sitting duck for automated scraping and brute-force attacks.

The Vulnerable Pattern

package main

import “github.com/gofiber/fiber/v2”


func main() {
app := fiber.New()


// VULNERABLE: No rate limiting middleware. 
// An attacker can flood this endpoint indefinitely.
app.Get("/api/resource", func(c *fiber.Ctx) error {
    return c.SendString("Resource accessed")
})

app.Listen(":3000")


}

The Secure Implementation

The secure implementation injects the 'limiter' middleware into the request lifecycle. By setting 'Max' and 'Expiration', we define a sliding window that drops excessive traffic. We use 'KeyGenerator' to identify unique clients via 'c.IP()', though in production behind a proxy, you should use 'c.Get("X-Forwarded-For")'. For distributed environments, configure the 'Storage' parameter to use Redis, preventing attackers from bypassing limits by hitting different load-balanced nodes.

package main

import (
“time”
“github.com/gofiber/fiber/v2”
“github.com/gofiber/fiber/v2/middleware/limiter”
)


func main() {
app := fiber.New()


// SECURE: Implement the official Fiber limiter middleware.
app.Use(limiter.New(limiter.Config{
    Max:          10,               // Limit each IP to 10 requests per window
    Expiration:   1 * time.Minute,  // Window size
    KeyGenerator: func(c *fiber.Ctx) string {
        return c.IP()              // Track by IP address
    },
    LimitReached: func(c *fiber.Ctx) error {
        return c.Status(429).JSON(fiber.Map{
            "error": "Rate limit exceeded. Try again later.",
        })
    },
}))

app.Get("/api/resource", func(c *fiber.Ctx) error {
    return c.SendString("Resource accessed securely")
})

app.Listen(":3000")


}

System Alert • ID: 7714
Target: Go Fiber API
Potential Vulnerability

Your Go Fiber API might be exposed to API Rate Limit Exhaustion

74% of Go Fiber apps fail this check. Hackers use automated scanners to find this specific flaw. Check your codebase before they do.

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