Why am I seeing "TypeError: Failed to fetch" even when my fetch request gets a valid response?

General Discussions
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1

If you’re encountering a “TypeError: Failed to fetch” despite getting a valid response, it usually points to a CORS issue, network error, or credentials misconfiguration not a fetch syntax problem.

One likely cause is including credentials: “include” in your request, which requires the server to send proper CORS headers (like Access-Control-Allow-Credentials: true).

If those are missing or misconfigured, the browser blocks the response and throws a typeerror failed to fetch.

2

Ah, I ran into this last month! My API was responding just fine, but I still got the dreaded TypeError: Failed to fetch.

It turned out my server wasn’t returning Access-Control-Allow-Credentials: true while I was using credentials: “include” in the fetch request.

Once I added that header on the server side, the error disappeared instantly.

So yeah, it’s not always a bad fetch call, it’s often CORS mischief.