Best practices for using the Vary headerBest practices for using the Vary headerWhat is Vary?Vary is one of the most powerful HTTP response headers. Used correctly, it can do wonderful things. Unfortunately, this header is frequently used incorrectly, which can lead to abysmal hit ratios. Worse still, if it's not used when it should be, the wrong content could be delivered. Instead of just pointing you to the Vary specification, I'm goi
