How can i save the values from the config.html in my extension?

So my extension is working like this right now:

→ User link with oauth the twitch account to the account on my website
→ The extension is sending the twitch channel id from the brodcaster to my api endpoint
→ my api is sorting out the right information from the channel id and sending them to the extension.

Is this a common way on twitch to handle the extensions ?