Most API teams reach for a Redis cache or a CDN long before they've spent the one HTTP header that does the job for free. Cache-Control lets clients, proxies, and CDNs cache your responses correctly without you running any infrastructure. Get it right and a huge slice of your traffic never touches your origin. Get it wrong and you either serve stale data or melt your database. Here's how to think about it.
The header that does the work
Cache-Control is a response header that tells every cache in the chain how long a response stays fresh and who is allowed to store it.
HTTP/1.1 200 OK
Content-Type: application/json
