Glossary term
What is preflight (CORS preflight)?
preflight stands for CORS preflight.
A small OPTIONS request the browser sends first. It asks: is this cross-site request with this method or these headers allowed?
Learn it properly · The Browser ContractLesson 4: CORS Explained: Same-Origin Policy, Preflights and CredentialsWhy CORS protects the browser and is not a firewall for the server, what makes a preflight request, and why you cannot use a wildcard origin together with credentials.