It is possible to register the letters a to z, the numbers 0 to 9 and the hyphen “-“. In addition, the following characters are allowed: á é í ó ú ä ë ï ö ü â ê î ô û à è ì ù ã õ ñ æ œ ç
However, it is not possible to register domains that begin or end with a hyphen “-“ or start with the characters “xn—“.