Mastering CloudFront Caching: How Cache Keys and TTL Shape Your Hit Ratio

Understanding CloudFront's cache policies is essential for optimizing edge performance and controlling costs—the right cache key and TTL configuration directly determines your hit ratio and origin load. Getting cache key strategy wrong means either treating identical responses as separate objects or serving stale content; TTL misconfiguration either hammers your origin with unnecessary requests or keeps outdated content in edge locations. This technical deep-dive explains the subtle interactions between cache keys, TTL settings, and origin headers, enabling engineers to move beyond managed policies and build custom strategies that fit their traffic patterns.