Browser & Web Performance · Senior · Question 37 of 75

What does `Cache-Control: immutable` change?

1Makes the response readable only once
✓Correct answer: Tells the browser not to revalidate the fresh response even on a normal reload
3Prevents CDNs from purging the response

Explanation

Without it, reloading a page could trigger conditional requests for every asset. It fits only content-hashed URLs.

Further reading

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