REST API rate limits are essential tools for maintaining server reliability and efficiency by controlling client request frequency to web servers, distributing resources fairly, and preventing server overload. These limits, which differ from API throttling, can manifest in various forms such as fixed-window, concurrent, geographic, and token bucket rate limiting, each serving different use cases and scenarios. While rate limits can be frustrating for users, they are crucial for ensuring optimal server performance, preventing abuse like denial-of-service attacks, and managing costs associated with high data transmission and server maintenance. Notable examples of rate limiting practices are seen in platforms like QuickBooks, HubSpot, and Salesforce, each employing strategies tailored to their user base and service requirements. Effective management of rate limits involves understanding API documentation, using HTTP headers for real-time limit status, categorizing endpoints by their rate constraints, and handling limits gracefully to prevent disruptions. Merge’s Unified API offers a streamlined solution by providing hundreds of integrations without the need to individually manage rate limits of different API providers, thereby simplifying and scaling integration efforts for businesses.