HTTP caching for https://amazon.com

Overview

✅

This resource can be cached.

This response can be cached because of a directive in the Cache-Control header.

✅

This resource has a cache control header.

Cache-Control: no-cache
❌

This resource does not have an entity tag.

HTTP response cache headers

These are the raw caching-related HTTP headers that were returned by the server:
cache-control: no-cache
expires: -1
vary: Content-Type,Accept-Encoding,User-Agent
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Cache-Control

Cache-Control: no-cache
  • ♻️
    No Cache
    (RFC)
    The no-cache directive indicates that this response may be cached, but any cached response must be validated with the origin server before it can be used.
🗑️

Expires

The Expires header indicates the time at which the response will expire.

Expires: -1

In this case, the time is in the past, which means the response should be considered stale immediately.

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Vary

The Vary header indicates which request headers the server response may be dependent on. If any of the listed headers change, then the response may be different. This allows the server to send the correct cached response for each request. For example, ensuring that a client that does not support compression does not receive a cached compressed response.

Vary: Content-Type,Accept-Encoding,User-Agent

Accept-Encoding: The server response is expected to be different depending on the encodings that the client accepts via the Accept-Encoding header in the request. For example, if the client does not support compression, then the server may send a cached uncompressed response. If the client does support compression, for example, by sending a a Accept-Encoding: gzip header, then the server may send a cached compressed response.

User-Agent: The server response will depend on the user agent that the client sends in the request. Typically, this means that the server will cache responses for different browsers, operating systems, or devices.