I read all over but couldn't find the answer.

When I use FormData(), it returns status 404 bad request.

However, if I pass the data (hardcoded) as in const requestBody (example below), it works perfectly.

This is my code:

    var formData = new FormData();

    formData.append("nickname", "johxns");

    formData.append("password", "john_password");

    formData.append("email", "[email protected]");



    // If I do it this way, and assign this to body inside fetch, it works perfectly

    // const requestBody = '{"nickname": "johxns","password":"john_password","email":"[email protected]"}';



    fetch("http://localhost:5000/create_user", {

        // if instead of formData, I assign requestBody to body, it works!

        body: formData,

        headers: {

            "Content-Type": "application/json"

        },

        method: "POST"

    }).then(function(response) {

        return response.text();

    }).then(function(data){

        console.log('data', data);

    }).catch(function(err){

        console.err(err);

    });

I already tried with URLSearchParams, but still couldn't make it work.

Thanks.