Contracts for the sale of goods between parties in different treaty countries are governed by an international convention unless the parties exclude it — which many contracts do without realizing they had a choice, and many more fail to do at all.

Automatic application. Where both parties have places of business in contracting states, the convention applies of its own force. Selecting the law of a contracting state selects the convention, not that state’s domestic sales law, unless the clause says otherwise.

Key differences from domestic law. No writing requirement; a different approach to the battle of the forms, where a reply with additional material terms is a counteroffer; no parol evidence rule; a fundamental breach standard for avoidance; a right to require performance; and a notice requirement for non-conformity within a reasonable time with a two-year outer limit.

Excluded matters. Validity, property rights, and liability for death or personal injury.

Exclusion clause. To opt out, state expressly that the convention does not apply and identify the domestic law that does.

When it may be preferable. For sellers, the fundamental breach threshold for avoidance is higher than the perfect tender rule.

Incoterms address delivery, risk and cost allocation and should be specified with the edition year.