The 2 exams which are internationally recognized are the DELE and the SIELE exams.
The DELE (Diploma de Español como Lengua Extranjera) is the official diploma of Spanish language learning for the Cervantes Institute which is recognized around the world and is well respected in the spheres of education and businesses alike. The levels are A1, A2, B1, B2, C1 and C2.
The SIELE exam is an official diploma which certifies your level of Spanish. This exam can be taken online whereas the DELE must be taken in an institute recognized by the Cervantes Institute.