I will start by saying that the site color scheme is pretty sharp for my eyes. I think you'll have a more polished look by having the background be white with a more neutral color palette.
For the extension itself: I like that it doesn't call out for information unless called upon, but if I ask for information about a site, I see no reason for you to have to collect the full URL and POST it to /track. That could lead to unexpected data leakage (as some URLs could be sensitive). You should probably get those API calls over to using HTTPS as well.
Also with every lookup, my console gets the log message "asdf", which is kind of weird. One thing I noticed is that the extension is pretty slow to get information. It appears it calls out for each item individually, and this leads to seven unique calls to your API that could be condensed into one request / response. If an API call fails with a 500 error, the entire stacktrace is dumped to the user. You'll want to disable debugging mode in your Express app to ensure that doesn't happen.
Since these APIs are public, you might want to consider rate limiting by IP, or you might find that your extension isn't the only consumer of them. A free and open WHOIS or Geolocation API that responds with JSON could be abused by other app developers, and having that already around moves the cost from them to you.
For the extension itself: I like that it doesn't call out for information unless called upon, but if I ask for information about a site, I see no reason for you to have to collect the full URL and POST it to /track. That could lead to unexpected data leakage (as some URLs could be sensitive). You should probably get those API calls over to using HTTPS as well.
Also with every lookup, my console gets the log message "asdf", which is kind of weird. One thing I noticed is that the extension is pretty slow to get information. It appears it calls out for each item individually, and this leads to seven unique calls to your API that could be condensed into one request / response. If an API call fails with a 500 error, the entire stacktrace is dumped to the user. You'll want to disable debugging mode in your Express app to ensure that doesn't happen.
Since these APIs are public, you might want to consider rate limiting by IP, or you might find that your extension isn't the only consumer of them. A free and open WHOIS or Geolocation API that responds with JSON could be abused by other app developers, and having that already around moves the cost from them to you.