An offer is also called a quotation or a price. It refers to the act of one party proposing various transaction conditions for the purchase or sale of goods to the other party and expressing its willingness to reach an agreement with the other party and enter into a contract based on these conditions. In business, an offer is usually issued by one party after receiving an inquiry from the other party, but it can also be issued directly without the other party’s inquiry.

The validity period of an offer (or the acceptance period) refers to the period during which the offeree can exercise the right to accept the offer. In international trade, all offers have a validity period. Unless otherwise agreed by both parties, an oral offer is generally effective on the spot, and the effectiveness of the offer ends at the end of the conversation. For a written offer, the validity period may be clearly specified by the offeror in the offer, or it may not be clearly specified. The Convention stipulates: “The offer takes effect when it reaches the offeree.” The validity period of an offer takes effect from the time it reaches the offeree until the expiration of the validity period. The Opinions on Electronic Communications states that in electronic communications, the “arrival” of an offer refers to the moment when the electronic communication enters the offeree’s server.

Offers that do not specify a validity period are customarily effective at a “reasonable time”. What constitutes a “reasonable time” depends on the specific circumstances.