Gitlab API and the Same Origin Policy

We use Gitlab SaaS. We want our electron app to add new public keys to users with calls to the GitLab API. A few examples of the calls include…

…testing our ability to access the API:

https://gitlab.com

…getting an access token:

https://gitlab.com/oauth/authorize?client_id={...}&redirect_uri=http://localhost:8080/&response_type=code&state=${...}&scope=api&code_challenge=${...}&code_challenge_method=S256

… and getting the user ID that corresponds to an access token:

https://gitlab.com/oauth/token/info?access_token={...}

Our electron app uses Vue for the frontend. Here’s how we call the API in the methods section of the app:

const currURL = gitlabWindow.webContents.getURL();
console.log(currURL)

const testAPI = "https://gitlab.com"

// This is the simplest possible API request we could make. We use it to test access.

axios.get(testAPI, {})
.then(function (response) {
     //handle success
     console.log("RESPONSE RECEIVED! Please reference the response below:")
     console.log(response);
})
.catch(function (response) {
     //handle error
     console.log("ERROR ALERT! Please reference the response below:")
     console.log(response);
});

gitlabWindow.close();

In the electron app, the calls return an error:

Access to XMLHttpRequest at 'https://gitlab.com/' from origin 'http://localhost:8080' has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource.

I thought we could blame the same origin policy here, since our app and gitlab.com are different hosts. But using postman to call the same URL works. Where does the error above come from?

Thanks for your help!