Caching Score: https://www.vcat.vic.gov.au/sites/default/files/2020-07/Chevron.png

What is this check, and why should you care

Having a cache hit ensures the fastest possible delivery of content to end users.

The response header X-Cache had a value of HIT.

Fastly has documentation on how to interpret the X-Cache header.

Maximum possible points

100

What is this check, and why should you care

Using a long cache lifetime helps to ensure a high cache hit rate.

In order to get maximum points, your cache lifetime must be greater than or equal to 4 weeks. If your cache lifetime is less, then you will get some proportion of the score based on how close to 4 weeks you are.

Current cache lifetime is 2628010 seconds (1 month and 2 days).

Maximum possible points

100

What is this check, and why should you care

Using a CDN is extremely useful for caching purposes.

Maximum possible points

50

What is this check, and why should you care

The time that it takes for a user's browser to receive the first byte of page content.

The lower the TTFB, the faster your site will be perceived by the end user.

In order to get maximum points, your TTFB must be less than or equal to 30ms. If your TTFB is more than 1 second then you get no points here.

Maximum possible points

50

What is this check, and why should you care

Using ETag identifiers is an easy way to ensure your visitors are always getting the most up-to-date version of the content. This mechanism allows caches to be more efficient and saves bandwidth, as a Web server does not need to send a full response if the content has not changed. HTTP 304 responses are used to indicate this is working.

An HTTP request with the request header If-None-Match with a value of "5f0d4efb-6060" was sent, and an HTTP 304 was responded with.

See the Wikipedia page on ETag for more background.

In order to get maximum points, you need to have ETag identifiers and an HTTP 304 response must be received when using a valid If-None-Match request header.

Maximum possible points

30

What is this check, and why should you care

Using Last-Modified headers is an easy way to ensure your visitors are always getting the most up-to-date version of the content. HTTP 304 responses are used to indicate this is working.

An HTTP request with the request header If-Modified-Since with a value of was sent, and an HTTP 304 was responded with.

Maximum possible points

30

What is this check, and why should you care

Having tiered caching can help improve the cache hit ratio of your site because it provides an additional layer of caching in front of your origin.

Maximum possible points

25