CORS No 'Access-Control-Allow-Origin' header

[Bobetti]

What version of Hono are you using?

4.5.1

What runtime/platform is your app running on?

Vercel, node

What steps can reproduce the bug?

I have two applications running on the local machine:

• client: static svelte application: http://localhost:5001/
• server: vercel function with honojs: http://localhost:3000/api/pricing

When client application sends POST request to the server from browser, getting error regarding cors.
Of course, no errors using Postman windows app. Server responds with needed data.

Client side code:

Server side code, post method just not on the screenshot, but it is present . Showing cors configuration:

Errors from browser:

I tried all solutions suggested here:
#895
#2318
#1872

Nothing working out.
Spent several days and can' get it working.

What is the expected behavior?

No response

What do you see instead?

No response

Additional information

Package.json file:

{
"name": "my-app",
"type": "module",
"_moduleAliases": {
"$lib": "src/lib"
},
"scripts": {
"start": "vercel dev",
"deploy": "vercel"
},
"dependencies": {
"@azure/data-tables": "^13.2.2",
"@hono/node-server": "^1.12.0",
"hono": "^4.5.1",
"luxon": "^3.4.4"
},
"devDependencies": {
"vercel": "^32.4.1"
}
}

[yusukebe]

Hi @Bobetti

Can you provide a minimal project to reproduce it?

[Bobetti]

@yusukebe

https://www.dropbox.com/scl/fi/cbp6d6yc81vbsmu67vxr0/minimal-projects.zip?rlkey=eazzklgmxswd7e8pbarthiqyt&e=1&dl=0

Top right Download button (arrow down).

Removed node_modules folders
In the server app - removed vercel folder.

Thank you for your efforts

[Bobetti]

@yusukebe
any updates for me?

[yusukebe]

Hi @Bobetti

I've investigated. It's not an Hono-side issue. Please upgrade the vercel package:

npm i vercel@latest

After that, you may face another issue: #1695, but this issue can be closed.

[Bobetti]

@yusukebe thank you for your help, very much!