API rate limits are mechanisms set by API providers to control the number of requests a client can make within a specific timeframe, ensuring server stability and resource conservation. These limits can vary significantly depending on the nature of the API, with methods such as Requests Per Minute (RPM), concurrent connections, and various algorithmic approaches like the Leaky Bucket and Token Bucket being commonly employed. The document highlights the importance of understanding these limits to prevent errors such as the infamous 429 status code, which indicates too many requests, or the invisible quota, where limits aren't communicated effectively. Effective management strategies include inspecting headers for retry information, queuing dropped requests, and using documentation to understand specific provider limits, with tools like Lunar.dev's Strategy-Based Throttling offering client-side solutions to manage rate limits proactively.