Newbie with Backend API question

I’m trying to create my first backend functions to do an ‘update’ to my collection.

I have ‘not’ published my site yet but I have “saved” my current changes (it is a premium site). Should I still be able to reach the backend endpoint for my function? I’m trying to test it from either a web browser on my computer or even through Fiddler running on my computer. Both are giving me a 404 error. So I was wondering if I’m doing something wrong or if this is even possible. The function name I’m trying to reach is “put_nextSong” and I’m calling it like the following:
{In Fiddler I’m selecting it to be a PUT}
https://{mydomainname}/_functions-dev/nextSong
{providing a simple test JSON formatted string in the body}

Everything I’m reading, it seems like I should be able to do this on a non published site using the functions-dev part of the address. I’ve also tried the function name with and without the "put" prefix on it. Unless this can only be done from my actual web pages from within the site.

I appreciate any help I can get on this.

Hi John,

The backend (server-side) files are only available to a Wix Code client (front end). First, you can get an overview of backend files , and then you can read more about backend in the article Calling Server-side Code from the Front-end with Web Modules .

Have fun,

Yisrael