Sworn interpreting means that the interpreter is legally responsible for his or her work.
Official sworn interpreters are highly skilled professionals who work mainly in courts of law and at notarial proceedings and notarisations, but there are also other occasions when the presence of an official sworn interpreter is necessary. These include statements made under oath, the formalisation of contracts, marriages at a Spanish Civil Registry Office, etc.
Sworn interpreters are accredited by the Spanish Ministry of Foreign Affairs, which allows them to certify the accuracy and precision of their work using their signature and stamp.