This error occurs when the server limits requests. Implementing rate limiting or optimizing requests can prevent it.

The 'Too Many Requests' error in a Node.js API often results from clients exceeding the server's rate limit, either through high traffic or repeated requests within a short period. To manage this, implementing rate limiting is essential. In Express, for example, the express-rate-limit middleware allows you to define request thresholds per client based on IP address, blocking or throttling requests once the limit is exceeded. Configuring a short cooldown or delay time for subsequent requests can help distribute server load while allowing high-priority requests through. Additionally, caching responses for frequent requests reduces the need for repeated calls to the server. Redis-based rate limiting can provide more granular control over limits by tracking user activity in real-time and applying exponential backoff to handle increased traffic smoothly. In cases where your application is accessed by different clients, such as browsers and mobile apps, separate rate limits per client type can optimize the experience. API Gateways, such as AWS API Gateway or NGINX, can further reinforce rate limiting with additional controls. Properly setting HTTP headers for Retry-After can also help clients understand when they may try their request again, avoiding further overload.