API Throttling

API throttling is the practice of controlling the rate at which an API processes requests by limiting throughput - either per user, per endpoint, or globally. While rate limiting sets a hard cap on requests within a time window, throttling may shape traffic more dynamically, slowing down requests rather than outright rejecting them.

Throttling protects API infrastructure from overload, ensures fair resource distribution across consumers, and prevents any single client from degrading service for others. It can be applied at multiple levels: per API key, per subscription tier, per IP address, or per endpoint.

From a developer's perspective, throttling manifests as slower-than-expected response times or 429 Too Many Requests errors. Building robust retry logic with exponential backoff, respecting Retry-After headers, and implementing request queuing in your API client are the standard mitigations.