While benchmarking different CDN providers, I’ve noticed that Netlify has a suboptimal use of the
- Clients (visitors of Netlify’s sites, browsers) miss their local cache
- Thus it increase the requests to Netlify’s edge servers which result in an increase in bandwidth usage, which has a cost
- It also result in a increase in the TTFB, especially for resources like
.jpgbecause even when a resource should be fetched from browser’s cache, it result in a network request.
Netlify set the
Date HTTP header to the date when the CDN server cached the resource, instead of the time the request is server.
Due to that, Browsers are misusing their local cache, which increase TTFB and bandwidth usage.
You can read here the detailed math: https://forums.aws.amazon.com/thread.jspa?messageID=807813
Edge servers must set the
Date Header to the time the request was served.
They can use the
last-modified header to indicate when the file was modified.
It will result in improved local (browsers) cache hit by all visitors, which will reduce bandwidth usage, TTFB and costs.
Examples in the wild
Both Firebase hosting and StackPath are setting the
Date header to the time the request is served, and the
last-modified header to the time the site is deployed.