Comparative law notes
If the context is the contract formation process (i.e., an offer and acceptance to form a contract), then this English term is better.
There are multiple definitions - click on the translation that matches your context.
Anbieter
Substantiv
full
offeror
noun
Definitions of offeror
a person who makes an offer
An offer is deemed (=considered) accepted when the offeror has received an acceptance at the place and in the manner indicated.