Originally made by our community member Tithen-Firion, the SteamTrade Matcher userscript allows the automatic selection of all items in the trade offer window, making it a lot quicker to send trade offers.
The script modifies the Steam trade offer window to allow a few new parameters which make it possible to automatically fill the offer with all the items that were matched by SteamTrade Matcher.
With simple matches, like when you and the other user need the same number of cards (N for N matches), all of the cards will be added to the trade offer. In matches with multiple choices of items (N for N*X matches), SteamTrade Matcher will automatically add the best possible selection of items.
First of all, you will need an userscript manager extension for your browser, like Tampermonkey if you're using Chrome, or Greasemonkey if you're using Firefox. You will not be able to use the SteamTrade Matcher userscript without a manager.
Then, just click on the button below to download the userscript, choose "Install" and you should be done! Now, you can go try to send a trade offer using SteamTrade Matcher.
After installing, refresh this page to access the userscript configuration page.