SEO Atlas
TechnicalCaching headers

Cache-Control

The HTTP header governing how browsers, CDNs and proxies store and revalidate a response, using directives such as max-age, s-maxage and stale-while-revalidate.

In full

Hashed static assets should be served `public, max-age=31536000, immutable`, while HTML usually needs a short or zero max-age with revalidation so content changes propagate. `s-maxage` targets shared caches specifically, and `stale-while-revalidate` lets an edge serve a slightly stale copy while refreshing in the background, which is a cheap TTFB win. Misconfigured caching is a classic cause of a site appearing not to update for search engines.

Example

Setting `Cache-Control: public, s-maxage=600, stale-while-revalidate=86400` on article HTML gives an edge-cached response in single-digit milliseconds.

Related terms

ETag and conditional requests

A validator token identifying a specific version of a resource, allowing clients and crawlers to revalidate with a cheap 304 Not Modified…

Content Delivery Network

A distributed network of edge servers that caches and serves content close to users, reducing latency and offloading the origin.

Time to First Byte

The interval between a navigation request starting and the first byte of the response arriving; a foundational input to LCP and a signal…

HTTP/2

A binary, multiplexed version of HTTP that carries many concurrent requests over one TCP connection with header compression.

Edge SEO

Implementing SEO changes in CDN edge workers rather than the origin application, so fixes ship without touching the main codebase or…

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