Why is my IP Lookup Tool failing with a 'CORS policy' error when calling a Geolocation API?

Hey Lucia Rodriguez,

I understand the frustration with CORS policy errors; it's a very common roadblock when dealing with client-side requests from a browser environment like a Chrome extension. The Access-Control-Allow-Origin header being absent means the Geolocation API server isn't explicitly telling your browser that it's okay for your extension's origin (chrome-extension://...) to access its resources. This is a fundamental browser security mechanism.

For a Chrome extension, the most direct solution is to declare the API's domain in your manifest.json file under host_permissions. For example, if your API is https://api.example.com, you'd add "https://api.example.com/*" to your host_permissions array. This grants your extension the necessary permissions to make cross-origin requests to that specific domain. Ensure you are using Manifest V3, as permissions handling has evolved. If the API itself doesn't send the Access-Control-Allow-Origin header (which is often the case for public APIs expecting server-side calls), you might need an intermediary. In such scenarios, setting up a simple server-side proxy is the most reliable approach. Your extension would call your own backend server, which then fetches data from the Geolocation API and returns it to your extension, bypassing the browser's CORS restrictions because the request from your backend to the API is not subject to CORS.

Are you working with Manifest V2 or V3 for your extension, and do you have the ability to spin up a small backend service if needed?

That's a solid breakdown on the host_permissions and the proxy idea. I'm on Manifest V3 so that's good. Kinda leaning towards the proxy if the API is super strict. Others in this thread #ip-lookup-tool will def find this helpful.