A US apostille is a certified document that proves a public record is legitimate when used abroad. It does not serve as a translation, a visa, or evidence that the details in the document are accurate. Instead, it shows that the person who signed or issued it is an authorized official.

The Hague-Convention of 1961 established the apostille system through an international treaty. This treaty has been signed by 129 participating countries, including the United States, which joined in 1981, and Spain, which became a member in 1978. Since both countries are part of this treaty, Spain accepts apostilles as valid authentication for documents from the United States. If Spain is your destination, the apostille is the only internationally recognised form of document authentication the country accepts.

An apostille from the US is crucial when you need to use American documents in Spain. Authorities in Spain cannot confirm if US documents are authentic, so they depend on the apostille system set up by the Hague Apostille Convention. This system provides a certificate that shows the document is legitimate and issued by an official authority. Without it, your documents have no legal validity in Spain, and government offices, courts, universities, or notaries there will reject them.