Is it mandatory to initial every page of a contract for it to be valid? SIC Verifica investigates

Under Portuguese law, it is not mandatory to initial every page of a contract, such as a rental or work agreement, for it to be legally valid. The law only requires the document to be in writing and signed by the parties involved. While initialing pages is recommended by legal experts as a security measure to prevent unauthorized page substitution or alteration, its absence does not invalidate the contract.