Preview server mode in REACT mode Cors (inbound)

Support
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1

Hello,

I start with netlify in Preview servers mode, I already have my server running in production mode, and I’m not having any issues.

However, with the server preview mode, I’m having a CORS issue with incoming requests from my server.

Access to fetch at 'https://devserver-beta--*****.netlify.app/manifest.beta.json?time=1744969585658' from origin 'https://*****.****.io' has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource. If an opaque response serves your needs, set the request's mode to 'no-cors' to fetch the resource with CORS disabled.

I added:
netlify.toml:

[[headers]]
for = "/*"
[headers.values]
Access-Control-Allow-Origin = "*"
Access-Control-Allow-Methods = "*"
Access-Control-Allow-Headers = "*"

In path “public” _headers:

/*
Access-Control-Allow-Origin: *
Access-Control-Allow-Methods: *
Access-Control-Allow-Headers: *

However, Netlify doesn’t seem to take this into account in this mode (because it works in normal production mode).
OR
I’m wondering if requests to the preview server mode would be authenticated? If so, can we remove this authentication (I can’t find any relevant documentation on the subject)?

Thank you for your help.

2
3

Hi, thanks for the feedback, but I understand my problem, indeed the Preview Server mode is only made for authenticated team users, so this use case is not for me.

Thanks