CORS issue when working with express and react

[hrishikesh]

[Support Guide] Handling CORS on Netlify

Last reviewed by Netlify Support in July 2025 CORS stands for Cross Origin Resource Sharing. It is a HTTP header that tells the browsers how to handle a request from a certain origin to for an asset on your website. You can read more about it on Cross-Origin Resource Sharing (CORS) - HTTP | MDN (mozilla.org). By definition, an origin consists of scheme, domain and port. For example: https://www.example.com/ https:// is the scheme www.example.com is the domain 443 is the port (HTTPS is serve…