Contract formation

In Swiss contract law, a contract is generally formed when the parties reach mutual assent on the essential points. This usually occurs through an offer and an acceptance, expressed orally, in writing, electronically, or by conduct. Many contracts need no special form, but some require written form, notarisation, or registration. Formation must be distinguished from validity: an agreement may exist yet be voidable or ineffective because of defects such as incapacity, illegality, mistake, fraud, or duress.