A spot rate is a transportation rate that is based on the current market conditions and is generally valid for a short period of time, usually a day or a week. Spot rates are typically used for ad-hoc or one-time shipments, and are subject to change based on factors such as fuel costs, demand for transportation, and capacity availability. They are typically higher than contract rates, but can be lower than ad-hoc rates. Spot rates are usually offered by carriers or logistics companies on a first-come, first-served basis, and are usually used for shippers that have a less predictable or urgent shipping needs. This type of rate is commonly used for shipping by sea or air, it can be negotiated by shipper or freight forwarder with shipping lines or airlines.