Ben Borgers

How to allows CORS on Vercel functions

vercel

CORS is a browser feature that blocks HTTP requests from one domain to another, unless the destination has the proper headers set up.

I recently ran into these problems when making an HTTP request from my website to Potion, an API I build for Notion notes.

I fixed it by adding headers to my Vercel deployment that allowed HTTP requests from any domain.

Here’s my now.json (or vercel.json) file:

{
"headers": [
{
"source": "/(.*)",
"headers": [
{
"key": "access-control-allow-origin",
"value": "*"
}
]
}
]
}