How to implement rate limiting in async Rust

Use the governor crate with Arc<Mutex<RateLimiter>> to share state across async tasks. Add the dependency, initialize the limiter, and check it before processing requests.

use governor::{Quota, RateLimiter};
use std::sync::{Arc, Mutex};

let limiter = Arc::new(Mutex::new(RateLimiter::direct(Quota::per_second(10))));
let limiter_clone = limiter.clone();

let task = async move {
    if limiter_clone.lock().unwrap().check().is_err() {
        return Err("Rate limit exceeded");
    }
    Ok(())
};

Rate limiting restricts how often a specific action can happen, like a bouncer checking IDs at a club door. In async Rust, you need a shared counter that multiple tasks can safely update without crashing. This prevents your server from being overwhelmed by too many requests at once.