I want to figure out how to send TradeOffer immediately with objects.
If I just send a request

https://steamcommunity.com/tradeoffer/New/?partner= {ID} & amp; token = {token}

Opens a window with an empty offer. I also need to be subjects there. (Such as the return of items from the bot CSGolounge / Dota2Lounge)

Long wandering over the Internet, I realized that you need to send some POST request. However, how much I did not try, I could not send correctly.

What kind of post request must be sent to come TradeOffer like a bot CSGolouge / Dota2Lounge?

Answer 1, Authority 100%

You need a shopping bot.
Bots for such purposes there are already ready:

First Bot : Written on C #

guide on the second bot : Written on Node.js

In both cases, you need programming knowledge to make them work as you need.

Otherwise, it is impossible to send offer “POST inquiry” or some kind of reference, everything is much more complicated.