How can I use lootlocker without SDK? Does http get/post request works with api website? What parameter list requiered to post a new record?

hmm you can use http get post, there is doc at https://ref.lootlocker.io/game-api/#introduction
you can basicly strap on Guest login at least thats what i did.
Simple flow  StartSession -> SetName -> SendScore -> LoadLeaderboard