CSGO Trader is a browser extension for Chrome and Firefox that is designed to help with CS:GO trading. I started by adding functionality that Steam Inventory Helper lacked, but it already has SIH's most important features and much more.
The extension is available in the Chrome Web Store and at AMO. These release versions are usually updated every 1-2 weeks. If you have a browser that is not Chrome or Firefox don't worry, not all is lost. If you have a Chromium based browser like Opera, Ungoogled Chromium, Brave or the new Microsoft Edge you should be able to install the Chrome version. If you are on Safari though, all is lost for you because there is no plan to port it for your browser.Get it from your browser's marketplace:
Or to install the in-development ("nightly") version, download the code and follow these instructions (from after "Create a Manifest")