Introducing a Rate Limiter Library for Go

Source: Dev.to

Overview

In modern backend systems, rate limiting is essential. Without it, APIs are exposed to abuse, resource exhaustion, and unfair usage. This library provides a production‑ready, thread‑safe rate limiter for Go, based on the Token Bucket algorithm.

Why the Token Bucket Algorithm?

• Allows controlled bursts of traffic
• Provides smooth request flow
• Widely used in production systems
• Simple to understand and reason about

Each client gets a bucket of tokens that refills over time. Requests consume tokens — once the bucket is empty, requests are rejected.

Features

• Production‑ready & thread‑safe
• Token Bucket algorithm with burst support
• Fast in‑memory storage
• Detailed rate‑limit results (remaining, Retry-After, reset time)
• Extensive unit tests and race‑condition testing
• Optional cleanup for stale entries

Usage

import (
    "fmt"
    "time"

    "github.com/yasserelgammal/rate-limiter/limiter"
    "github.com/yasserelgammal/rate-limiter/store"
)

config := limiter.Config{
    Rate:     10,
    Duration: time.Second,
    Burst:    20,
}

store := store.NewMemoryStore(5 * time.Minute)
rateLimiter, _ := limiter.NewTokenBucket(config, store)

if rateLimiter.Allow("user123") {
    fmt.Println("Request allowed")
}

With just a few lines, you get a reliable rate limiter ready for production.

Use Cases

• REST APIs
• Go microservices
• Public‑facing services
• Internal tools
• Anything that needs fair and controlled request handling

License & Contributions

The project is open source under the MIT license and welcomes contributions.

GitHub Repository – rate‑limiter

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