Browser & Web Performance · Junior · Question 57 of 75

What is a CORS preflight request?

1The first request after the page loads
2A request that warms up the server cache
✓Correct answer: An OPTIONS request the browser sends first to ask whether the actual cross-origin request is allowed

Explanation

It's sent for non-simple requests, for example with PUT, DELETE, a JSON Content-Type or custom headers.

Further reading

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