API polling is a method where a client repeatedly requests data from a third-party API at set intervals, typically to accommodate varying data update frequencies. While API polling can enhance predictability and control over request frequency, implementing it effectively can be challenging. Best practices include setting polling frequency based on data change rates, using exponential backoff to handle request errors, incorporating error-handling workflows, and notifying users of delays. Performing load testing and understanding API pricing models can optimize polling strategy and costs. Merge offers a unified API platform that streamlines these processes, allowing users to build once and manage multiple integrations efficiently, while adhering to individual vendor requirements like rate limits and pagination.