HTTP Cache Control Directives (Types)

Question

ICSM Computer · Answer

HTTP Cache Control Directives (Types) Directive Description public Can be cached by any cache (browser, CDN, proxy). Safe for shared caching. private Can be cached only by the browser. Not cached by shared caches like proxies. no-cache Cached copy must be revalidated with the server before being used. no-store Do not cache at all — not even in memory. Best for sensitive data (e.g., login). max-age=n Specifies how long (in seconds) the response is considered fresh. s-maxage=n Like max-age, but specific to shared caches (e.g., CDNs). must-revalidate The cache must check with the server before using expired content. proxy-revalidate Like must-revalidate, but for shared caches. immutable Indicates the response won’t change, so no need to revalidate. stale-while-revalidate Allows serving stale content while revalidating in the background. Examples 1. Public Can be stored by browser and intermediate caches (CDNs, proxies).Good for static files like images, CSS, JS. 2. Private Only the end user's browser can cache this.Useful for personalized content (e.g., user dashboards). 3. No-Cache Cached, but must check with server before using.Safer when data might change frequently. 4. No-Store No caching allowed. Not stored in memory, disk, or anywhere.Used for sensitive data (e.g., banking, login pages). Summary Table Directive Can Cache? Who Can Cache? Needs Validation? Use Case public Yes Anyone (browser, CDN) if fresh Static resources private Yes Browser only if fresh User-specific pages no-cache Yes Browser or CDN always Dynamic but not sensitive no-store NO Nobody always Passwords, banking info max-age=3600 Yes Depends on public/private for set duration Control how long it's fresh

Directive	Description
`public`	Can be cached by any cache (browser, CDN, proxy). Safe for shared caching.
`private`	Can be cached only by the browser. Not cached by shared caches like proxies.
`no-cache`	Cached copy must be revalidated with the server before being used.
`no-store`	Do not cache at all — not even in memory. Best for sensitive data (e.g., login).
`max-age=n`	Specifies how long (in seconds) the response is considered fresh.
`s-maxage=n`	Like `max-age`, but specific to shared caches (e.g., CDNs).
`must-revalidate`	The cache must check with the server before using expired content.
`proxy-revalidate`	Like `must-revalidate`, but for shared caches.
`immutable`	Indicates the response won’t change, so no need to revalidate.
`stale-while-revalidate`	Allows serving stale content while revalidating in the background.

Directive	Can Cache?	Who Can Cache?	Needs Validation?	Use Case
`public`	Yes	Anyone (browser, CDN)	if fresh	Static resources
`private`	Yes	Browser only	if fresh	User-specific pages
`no-cache`	Yes	Browser or CDN	always	Dynamic but not sensitive
`no-store`	NO	Nobody	always	Passwords, banking info
`max-age=3600`	Yes	Depends on public/private	for set duration	Control how long it's fresh

interview

HTTP Cache Control Directives (Types)

Can you answer this question?

1 Answers

HTTP Cache Control Directives (Types)

Examples

1. Public

2. Private

3. No-Cache

4. No-Store

Summary Table