Fetch Does Not Work In API Serverless Function
Next.js ships with its own implementation of
fetch that
extends the native fetch
API.
I ran into a bug recently that was only reproducible in production. I had a
Next.js API function that was POSTing to another API endpoint using fetch.
I tested it several ways in development. It worked great. However, once the
feature was in production, it was silently failing. After some console.log
debugging, I discovered that the target API was getting an empty body in the
POST request.
I don't know the specifics of why, but somehow the fetch implementation
running in the Vercel serverless function environment apparently strips out the
body of a POST request.
The solution, for me, was to add the
node-fetch package and import
that version of fetch in my API function. Once I made that change, my feature
was working again.