Accessing get_metadata endpoint without Dropbox Javascript package

While we recommend using the official libraries, it's not required. You can always call the Dropbox API HTTPS endpoints directly if you prefer. The documentation covers the requirements for each endpoint, and includes an example of calling using curl, e.g., for /2/files/get_metadata.

It looks like you're running in to a CORS issue though, due to your use of `credentials: 'include'`. Dropbox API calls, such as for /2/files/get_metadata, are authenticated using Dropbox API access tokens, not the browser's credentials. You need to supply the access token in the "Authorization" header as a "Bearer" token. (Also, the parameters should be a JSON string in the body.)

So, you code should look more like this:

            fetch(apiURL, {
                method: 'post',
                headers: {
                    "Authorization": "Bearer ACCESS_TOKEN_HERE",
                    "Content-type": "application/json; charset=UTF-8"
                },
                body: JSON.stringify(reqData),
            })